This is a REALLY REALLY LONG PROCESS! Might be even longer than the Main Story! (maybe 4 times!)
I can confirm that the encyclopedia is NOT needed for this achievement as that is the only one I have not completed due to a glitch.
What you need to do is first look at your DNA TRACKER
Everything and anything in there is required for this achievement!
You need a grand TOTAL of 17070 points
This is what you need to get this achievement:
Challenge levels will be labeled as C1,C2,C3
----100% SYNC Main missions----------------------------------------------------------
Sequence 7- To be undetected by air assassinating a grenadier also. Right ship go through the back and wait until each guard walks opposite directions, light fuse and jump off. Left ship go through the side where cannons are not firing. take out the guard looking out into the water when grenadier isn't looking. Then make your way to the right side of the boat behind the crates. Whistle and kill the guard then whistle again for the grenadier and jump on the crate to air assassinate him. Rinse and Repeat for the last guards.
----Hunting Society missions------------------------------------------------------------
Find the cabin directly east of the most northern area of the frontier, it's right on the trail, can't miss it. East of the fort location there.
----Hunting Society Challenges (1,2 & 3)-----------------------------------------------
----Boston Brawlers Missions--------------------------------------------------------------
Tournament location is right here-
----Boston Brawler Challenges (1,2 & 3)-------------------------------------------
C3--Save your money or go hunting because you need to buy EVERY weapon in the shop!
----Frontiersman Missions--------------------------------------------------------------
These are really easy, just look for the icon on your maps and just do them.
----Frontiersman Challenges (1,2 & 3)----------------------------------------------
[ Find George Washington ] in Sequence 9.1. When you gain control of Connor turn around, look for the W on your map and get your conversations recorded. You also need to speak with him in New York post game.
You have to reveal a total of 90% of the map. A large portion of New York and Frontier cannot be revealed via Viewpoints alone. You have to walk/run the rest of it. The Frontier is a little easier, since you can just free run through trees to reveal the map faster, Newyork is a little trickier since the northern portion is mostly farmland
----Thief's Club Challenges (1,2 & 3)--------------------------------------------------
C3-[ Lure a guard dog with bait] - There is one dog in a rectangular size open sided building in West New York, along the main North,South street.
OR
Go to the Frontier. From there, fast travel to the Tavern at Lexington. Go south, there will be a officer and a guard dog. Use your bait once, kill the officer or escape and fast travel to the Tavern again. This will reset the enemies and repeat 2 more times for the challenge
C1-[catch a courier task]-wait around at a busy street and don't move, he will just come out of nowhere in a couple minutes. Also guards will start chasing you so just disregard them.
Steal everything a rich citizen has- If you follow the same person and keep pickpocketing them, you can steal stuff up to three times.
-----Liberate every area of Boston and New York----------------------------------
Most of these will appear on non liberated areas on the map, if not, run around said area and it will pop up and listen closely as people might be calling out to you for help.
---- Assassin recruiting missions--------------------------------------------
Will pop up after you have liberated a zone with the grand total of 6 assassins. You'll have to do missions first for them to unlock.
Another important tip is that they ALL need to be level 11 by the time your 84 contracts are finished. If they need some levels after contracts you can gain exp by summoning them in battle.
----Liberate FORTS--------------------------------------------------------------------------------
EVERY fort is in the corner of the every area.
----Discover all of BOSTON and NEW YORK underground.-------------------
The New York locations - South Market - will not be considered "discovered" until Sequence 11, which will turn it from 84% discovered to 100% These take a long time! Basically look for any routes going in a different direction then the other fast travel locations once underground. Make sure you have enough gun bullets also.
----Assassination Contracts------------------------------------------------------------------
You have to kill five targets that will appear on your map after you accept the assassination contracts.
----Courier Missions-----------------------------------------------------------------------------
These seem the only citizen missions not glitched as it will show up on your map automatically.
----Delivery Requests------------------------------------------- (credit MattyJWest)
MISSIONS WILL JUMP FROM 33,66 TO 100% FOR EACH AREA COMPLETED.
-West New York is on the docks, almost at the top of the district, just north of the white walled fort on your map
-East New York is slap bang in the center of his district, just a little north of a fast travel node.
-North New York is outside a building to the south of his district, near the docks, almost in a direct line south on the map from the fort fast travel node.
-Lexington Frontier Is just south of the Lexington fast travel, standing outside a tall white house on the east-ish side of town.
-Troy's Wood Frontier is in the northeast tip of the region, where three houses form a little triangle on the map.
-Valley Forge Frontier can be found the the west beach in this region, near a house which had a watermill if memory serves me right. Basically in the center and as far west as you can go in the region.
-Boston South is right on the border between South and Central Boston, where the southmost edge of Central meets the (almost) eastmost side of South. He's outside a house not too far away from the beach.
-I believe Boston Central was (this one is a little hazy) somewhere near the eastmost bridge leading over to Boston North.
----100% SYNC Naval missions--------------------------------------------------------------
----100%SYNC Naval Locations--------------------------------------------------------------
----100% Naval Privateer Contracts-----------------------------------------------------------
Another way to expose the powder stores is barraging front of the ship with your cannonballs. It isn't fail proof but it is safer since you don't have risk of taking much damage. The timing is a bit hard to land but so is ramming the front of the ship.
THE GIANT AND THE STORM-getting the 3 powder kegs to reveal themselves is very rage inducing but I finally managed to do it by chain shooting them and separating them quite a bit. Then I took my time and shot at the front of the ships to reveal the powder stores. Also you can come to a complete stop before shooting the bow of the ships but just make sure be careful of the main ship as it does have cannons in the front.
----ALL Homestead missions-----------------------------------------------------------------
These are easy as they will appear on your map automatically depending on how far you are in the story.
----Homestead inventions----------------------------------------------------------------------
After doing all the homestead missions for every artisan, grabbing the almanacs. Just start crafting all of them because you'll be able to purchase the resources in the stockpile in order to craft every invention.
COLLECTIBLES-Try to buy all the maps in the general store to make life easy for you
----Almanacs----------------------------------------------------------------------------------------
Before approaching these, make sure you have a set path that you can run in order to chase it to decrease the chances of losing it. If you don't want to wait for it, pick a fight with a group of guards and let them kill you and you will respawn in the immediate area.
----Open all chests ------------------------------------------------------------------------------
Some chests are underground so scan the perimeter to look for a cave entrance (the entrances are by rocks ) and there is one tricky chest in Lexington and there will be a cave opening from the top.
There is one chest in central Boston that is actually INSIDE a gamble house/tavern so it won't show on your map.
----Collect all Feathers--------------------------------------------------------------------------
These are in the frontier and mostly perched up in trees.
----Peg leg Trinkets-----------------------------------------------------------------------------
collecting all of these lead to the KIDD missions and yes they are required to be 100% SYNC and are listed under Naval locations
If you need any specific help with a challenge and/or mission leave a comment and I'll update it for everyone to see. If you have any tips i'll be happy to post it on here.
Some things will come easier than others but others will make you want to rip your fingernails out.
Credit too all the great comments before.Thanks a lot in making this guide better