Aside from the double Triumph result for droid chassis crafting, is there a way to make 2-3 minion droids that are identical? I assume you could also just spend any advantages the same across the board. Just curious though.

There really are no rules for it. The crafting rules have a built in assumption that everything you are doing is a unique project. You could spend advantages the same, but you run the risk of not getting enough on a particular check. Otherwise it's in solid GM territory.

I'd say if you can craft it once, you can craft it again, so you can either take the same difficulty plus whatever bonuses you got from Advantage the first time, or you can obviate the need for a check, you just can't get any bonuses from Advantage/Triumph.

The crafting rules are as Ahrimon said, in that outside of spending Triumphs/Advantages to get a duplicate build, each crafting attempt is meant to represent a unique and individual product. Said rules were never meant to be used to mass produce the same exact item over and over.

That being said, talk with your GM. Depending on the result you got for building the original droid minion, they might be okay with you just simply building more of those "off camera" with a suggested trade-off of paying two or three times the credits you paid to build the original per additional droid.