Here's the last version of my OpenLara mod which adds friendly fire, freelook, Lara randomly screaming, and a few other things.
Download link and more details here: https://github.com/FluffyQuack/OpenLara/releases/tag/1.1
And even more info about the mod here: https://www.patreon.com/posts/47455471
This isn't exactly super easy to set up and use. I originally made these changes for a co-op playthrough I did for Youtube, so my aim wasn't to make something very polished, just something which would make a co-op playthrough more novel and fun.