Jawas can really b in any book that features a decent amount of salvage operations taking place.
As for Tatooine, quite honestly that place should get its own source book, especially considering how many criminal empires, smuggling routes, and history takes place on said world. In addition, it seems to be a fairly decent world for desert survival training and research, in which both give it some good incentive for people to pay attention to.
Ugnaughts: I thought would have been in Jewel of Yavin, but that's an adventure module, not a source book. That could easily be another source book for either the EotE or AoR. I can picture that quite a few different species, specs, equipment, and locations would be needed in order to fill it out. Unless FFG decides to work with Kabam in making an "Uprising" Source Book.