Just something I'd like to point out here. Whether the Guarma animals are needed or not, the Trophy progress is seperate from your in game progress.
I'm in chapter 6, checked the Social Club Trophy tracker and both animal related Trophies were at 52% and 44%. I loaded a save file I have at the very beginning of Chapter 5 and checked Social Club again. The percentages were still at 52 and 44. SO, you could finish the game, skin/study everything and then reload to a previous save and pick up the remaining few animals and the Trophy would pop.
Your in game animal log would revert back to where your save file is, but the actual Trophy progress would not. So, as long as you have a save file from before Chapter 5, you'd be good.
I know it's looking like Guarma is not needed, but I just wanted to share anyways.