For the other two, I can think of two possibilities: they may be magistrate's names (a lot of names start with Aris... / Isa... would leave Isagoras/Isagores or maybe Isaurikos looking at Münsterberg).
Another possibility is that they're understood as city epithets. Aris(
ton) (the best) and Isa may refer to the value of Isegoria, political freedom & equality. There are some problems with both of these hypotheses of course (orthoghraphy and lack of parallels being the main ones), but maybe there's something I am overlooking.
Regards
Gert