For some reason I could not fit all the cheat codes in the description, however, I found an IGN article that has them all ...

GTA 5 mod that added GTA 4's Liberty City hit with a "friendly takedown" after contact from Rockstar, but the modders insist "there is no negativity between us" and the official devs ...

Reddit user breiner314 has posted the screenshots shared by Rockstar of GTA 5 in the run up to that game's release in 2013. They show cityscapes, vehicles and activities among other things.