All these achievements will come with normal story progression and are therefore unmissable. As I said in my solutions for the first episode there is no actual need for a solution as such. BUT I faced problems with these achievements not unlocking so I think it is useful to know when they should have unlocked so you know that your game has not glitched on you.
I will depict some events of the game after which the achievement should have unlocked.
Spoilers below:
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Very short Chapter. I got this one after talking to Frostfinger in Castle Black. As soon as the game switched back to Rodrick the achievement popped for me.
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For more information refer to the video (credit goes to IGN Walkthroughs):
Hope this helps you guys! ;-)
Any improvements? Let me know in the comments!