Apparently, someone did fix scripthook completely, but nobody knew about it. A friend got the link from FiveM devs, he then gave it to me to test it, and it spawned all cars and player models without any issues whatsoever. GET IT HERE.
Edit: EFLC seems to refuse to start for me with the fixed scripthook and snt at the same time.
Edit 2: Yeah, this only appears to work for IV, but not EFLC.
Thanks, will give it a try real soon. Its a shame it don't work for EFLC though !