First off, don't let this scare you too much, I know it had me really freaked out to begin with because I thought it was going to be impossible.
If you are going to vote negatively, please let me know why so I can improve the solution.
There are seven challenges, each with three stars:
1. Money Shots - Gather
Money shots is a challenge where you have to take dirty photos like in "It's All Greek To Me," I recommend that you use meg and switch to the second weapon in her lineup as that weapon is probably the best in the game. It may take a couple of times to get this, as it can be complicated to get the rhythm, but once you get the rhythm and figure out where you need to go, you should be able to get it pretty easily. Also for a good laugh, hit LB while playing with Meg.
2. Amish Amuck - Elimination
By far the easiest challenge. Pick Lois and switch to the same weapon used in the first challenge, I think it's the needler or something, and then just kill the fifty Amish guys and aim low to avoid the tourists.
3. The Crips and Ables - Rescue
I recommend Quagmire, use his main weapon, the assault rifle and go for headshots, but be careful to pick up health along the way because the handicap army can beat you down pretty easily. Otherwise this challenge is not too hard.
4. Town Hall Beating - Wave Defense
Again, not too hard, just kind of stay at the top of a flight of stairs and use the sixers, AW's good with the sixers. You can leave the "fortress", but I recommend you stay in it so you can be close to the ammo dump and health packs as you cannot find anything out in the field. Just stay in the three story building and use the sniper rifle to pick things off if they are keeping distance, also the sniper rifle is very effective against the robot mechs.
5. Sea Men Attack - Wave Defense
This one is less about actual wave defense and just staying alive for an allotted amount of time, I think it was about 3-5 minutes, just keep on the cannons. I recommend death, because his melee attack is incredibly efficient.
6. Last Minute Shopper - Escape
This one can be tricky, I used Meg, and also after picking up the first bomb, go right back to where you spawned and jump off the railing, similar to how you would get the seventh Rupert collectible in the Santa's Sweatshop level. This makes traversing the spinning gears much easier. After that you pretty much just keep going down and run out the front when you have the last bomb. One other thing to note is that you shouldn't really worry about the enemies, especially the ones that blow up, ace them if you can, but mainly just focus on picking up the bombs as quickly as possible and running.
7. Someone to Overwatch Me - Overwatch
This one can be a real pain in the ass. You will have to have two controllers, you can do it by yourself with two controller as I did. Planting the bombs and defending yourself with Lois is not too hard with her 'needler', but be wary of snipers, you can take them out yourself pretty easily. Now, the tricky part making the jump from the crane to the second building, this is what makes this challenge and this achievement a pain in the ass. The jump is very far and hard to pin down, it took me about ten or fifteen tries to get it right. I tried sprinting and jumping and everything else, but the way I finally made it was to stand at the left corner of the crane and jump - time it carefully - and you should make it. Plant the last four bombs and jump into the helicopter. I did not touch my other controller but once, to take out the snipers so I had time to plan and execute the jump carefully.
So, there it is, if you have any questions, please feel free to send me a message, otherwise drop a comment if I missed something or there is an addition you think I should make. Good luck.
From HyruleBalverine: the bonus challenges will not count towards completing the achievement