I was messing around with EC's Cheat device, using the teleport cheat to just play around with the in game scenes. Like the ones you just watch and everyone talks during them. I noticed something VERY IMPORTANT.
In some scene, i could press teleport and tony would simply disapear like expected (if you tap x at the beginning of a scene, it wont be skipped). But in all, i mean ALL the scenes that have the characters mouth moving, tony didnt teleport. This means one thing, this isnt an in game movie, its a cgi film. One of the reasons i was so surprised about the graphics was that i thought that somehow r* found a way to code in such a difficult task as stretching polys, but they didnt, instead i assume they made these short films off a PC or so, and set them to play.
Now, i'm only making an assumption, and this is the speculation section. Theres a great chance that the character modules are replaced by specially coded ones, so when i use the teleport cheat, it isnt the same tony. But this could be a huge reason why it doesnt work on 1.5, i mean i heard that the movies that are encoded at the beginning of the game can only be decoded on 2.00's prx modules, so this would mean that if these are littered throughout the entire game, thats why simply replacing the prx files in a backup iso doesnt work.