Ok, sorry for the late reply.
Firstly Napoleon Dynamite: As far as I remember health does in fact increase slightly after every fight (when you go back to the legion map). Secondly there are items scattered around the legion map which can reduce the AI difficulty which can make it easier.
For You Broke My Heart You state that guard primers regenerate over time, this is true. But let's say we have Tager, and he has 8 guard primers, if he break bursts (green) he will lose 4 guard primers permanently for that round (I.E they do not regenerate to the maximum of 8, but only regenerate to 4. max). Also Gold break bursts do not take away half of your primers.
For Fatality you state that it happens when you counter the opponent using certain attacks. This is correct but you do not state what attacks or give an example which can be used to easily grind the achievement. I know you say it'll happen naturally, but for me it didn't and I had to grind the achievement as I didn't have it after I completed Score attack, story, true ending AND Legion. So it's best to put an example which can be used for those that haven't unlocked it "Naturally".
For The Better Part of Valor the description says: "Do not take damage for 20 seconds while in Negative State, and win the round." yet you say it unlocks after 20 seconds automatically. Pretty sure you have to win the round.
For Loincloth festival Bang's Astral has to be done Mid-air.
Same for They Call Me MISTER Tiddles! Bang's Astral is incorrect.
For I Can Do This All Night the achievement will become invalid if you just stand still and do nothing, in other words you have to be actively moving for that 1 hour. You haven't stated this.
This is what I've noticed as I briefly read over the guide. I haven't played this game in a long time, but I'm 99% sure everything I have posted is correct. If there is anything wrong tell me.
Thanks to Rajeanero for the signature.