After figuring out how to fix rigging issues for 2 days non-stop here it is, with this default cj ped and cutscene model now you can replace anybody with default CJ!

i tried making this as accurate as possible so enjoy!

Also before commenting, no requests for your custom cj, i am already as tired as it is and will no longer continuing this, i am not a rigging expert, that's why it took me 2 days :P

Into more detail in what i basically did:
I merged CJ parts for the cutscene model and merged them to csplay.dff bones into blender, the arms we're not rigged well, so i used woozie's cutscene model's arms bones and somehow that worked,

For the ped model (this genuinely took more time than the cutscene one to figure out)
I merged CJ parts for the ped model and merged them to player.dff bones into blender, the clavicle and upper arm bones we're not rigged well, so i tried to manually weight painted them to look more like the woozie ped arms and hey that worked (i know that's not accurate to the actual player model but it was the only solution that worked without figuring out rockstar's coding magic).

Also this was the simplified version of what i did, in the process i was actually trying out alot of random stuff to see what works and here i am.

Tools Used:
RW Analyze (For seperating clumps)
3ds Max 2016 (For Importing and exporting models)
Blender 3.4 (For merging models easily and without any major hiccups)

Scripts Used:
The Hero's DFF importer and exporter for 3ds max