Mario & Tyler:
I may not be much help, but here goes!
As far as which bushings to replace... ALL OF 'EM. Remember, your talking about a front end set up that's 26 years old. Want to know which bushings are which? Cruise by your library and hunt down a shop manual for the 76 Mustangs, photocopy the page and voila!
Now, where to buy... check your local Napa and CarQuest parts stores if you have any there. I've also got a 72 Mustang and you'd be surprised what these folks have in stock or can get from a warehouse overnight at a VERY REASONABLE PRICE. If you just can't find anything, check with some of the Mustang rebuild magazines like California Mustang or Mustangs Unlimited and ask for a catalog.
Surprisingly, even though you can't find much in the way of body/restoration parts for the "Mini-Mustangs" you can find suspension parts because so many of them were scavenged by the Street Rodding fanatics. That also gives way to checking with some of the street rod companies who sell the Mustang II "mock" front ends/suspensions. Pick up a street rod magazine the next time you're at the supermarket and see what's available... you might even see the colored ones you were talking about.