As for status earning, based on the OP's situation and preferences, I'd also recommend consolidating and going for mid-tier tier in one, rather than low tier in two. Like sdsearch posted, low tier doesn't get you much and this is even more so with the things the OP is most interested in. And between the two, I'd pick UA for generally the same reasons others have stated upthread.

With the CC miles and consolidation vs. spreading out... it's good not to have all of your eggs in one basket, due to devaluations, strengths and weaknesses of each program/airline/alliance, etc. However you don't want to spread things too thin such that you're slow to earn some useful balances to redeem. I tend to re-evaluate my future travel goals periodically and adjust my CC activity (bonuses and everyday spend) as best I can accordingly. Also on occasion a really, really good CC bonus may come along that I didn't plan for (like the original BA 100K Chase card a few years back, for example) and that causes me to shift the spend a bit differently.

Guess that doesn't really answer the question, but it's probably one where there will never be on clear answer for all.