Not a bad idea. Though I'd have it that if you repair him during the prologue, he still shows up in the Dock Storage area, where you would be able to repair him again(because he woud've been damaged by HK-50, like T3, and you could do it either as T3, or as the Exile when he/she gets into the dock area). Though if you don't repair him at all then, the TSF could find him, or of course you would find him on Korriban.
As to him coming with you on the Hawk, no matter where you'd find him, maybe he could serve some fuction(Medical - though not in the Medical area itself[between Mical, and the restored Lab station, it gets a bit crowded], etc). Though not exactly a party member, similar to the Remote(though not a puppet to anyone).
This might be a bit much for what you're planing, however.