Mods Used:
Forge Modloader v 32.6.0
FirstPersonMod v 2.0.0
notenoughanimations v 1.2.3
TRansliterationLib v 1.0.3

Game hardcrashes when loading into a world, have isolated it to this mod specifically. A brief glance at the logs suggests something to do with crossbows and arm rendering being the source of the problem?

The sooner this can be looked into the better, as the additional features of this mod would be very nice to have.

Crash Log: https://pastebin.com/yHduDBpq

Ah, that's just the versions that showed up when I installed the mod through AT Launcher. What version(s) of the mod(s) should I be installing for proper functioning then?

Well 1.16 Not enough Animations is 1.2.4 and should require the TRansliterationLib 1.0.4(the latest version), and for FirstPersonMod 2.0.1. No clue where ATLauncher gets these versions from, but for example, the TRansliteration lib update is from March last year.
Note: I don't use 1.16 anymore, especially Forge, so I kinda guess that the latest versions of everything should just work.

Eh that's a looong outdated version? And for that version TRansliterationLib(not maintained anymore) is outdated/the wrong version.