In disk one you cannot rent out the chocobo stables and therefore not be able to get a golden chocobo. Also you need to get a nut from some goblins on goblin island which can ONLY be accessed using the Highwind. Also you have to get some stuff from the chocobo sage in order to make a green or blue chocobo, and you can ONLY reach the chocobo sage once you get the airship. You get the airship in Disk 2(I think) but you still can't rent out teh stables till Disk 3. On the 3rd disk if you go to teh chocobo farm, he will say "why doncha breed some chocobos before the world ends eh?" or something along those lines. I am not entirely sure at what exact moment in the game you cna rent out stables but I did it in disk 3. *shrugs* And about the Tiny Bronco replacing the Highwind thing, I've never seen it done, but It may be possible on PC.