OK I'll post.
Las Vegas - not a base for anything as far as I know.
PHX - it's my opinion, based on the current distribution of reserves and the way FO standing bids are coming out and the fact that recruiting is promising people they can have any base they want that Mesa was assigning new hires their first request. They may no longer be doing that, but that's what I think they were doing. So if they ARE doing that, and keep doing it, and you bid PHX, and you get the Mesa CRJ or Dash you'll get PHX. Now if they involuntary displace out of PHX to re-align the bases to what a normal airline would have, bye bye PHX.
If you go to PHX as a junior FO, expect to be junior assigned to TDY somewhere else, probably IAD - but at least the company provides and pays you for the commute.
As far as I know junior on the Dash is still GJT, junior on the Mesa CRJ is IAD, junior on the Freedom ERJ or CRJ is JFK. When base assignment was normal most people who get IAD in training get ORD before they finish IOE if they want it.
What was the other question? Oh equipment - who knows, nobody knows how Mesa assigns people to equipment - playing the odds, Mesa CRJ, Freedom ERJ, Mesa Dash and Freedom CRJ - but that's just the odds, whole classes go to one equipment type sometimes.
I hope that's helpful.