Fly Casual doesn't offer anything with a high Intellect; they mostly focus on more social roles.
Jawas are not anywhere official; the unofficial menagerie stats were made by a few beta players, and err on the side of conservative stats, so it shouldn't break anything.
Gadgeteer is a solid specialization, and using tech is built into the concept. The have a number of talents that focus on outfitting gear (Jury Rigged and Tinkerer), but they are indeed a very good combat specialization. But they are primarily Bounty Hunters , so that should be considered when making a character.
Species with high Intellect exist. Lords of Nal Hutta and Suns of Fortune have one each, Enter the Unknown has at least one. I know Stay on Target, Lead by Example, and Forged in Battle all have one at least. More can be found in Force and Destiny books.