Question: is there anyone doing QA on the new 95.1 OSX binaries?

Not particularly. IIRC goatpig does not have a mac to do testing with. There is really only one person who contributes mac stuff for Armory.

I'm facing a string concatenation error when armory tries to load on this machine. Am unsure if it's my system or armory...

AFAIK, Armory does work on Macs. It could be an issue with mac versions, I don't remember what version Armory was last tested on.

I personally debugged 0.95 on Mac. I believe it was on El Capitan.

Is there anyway to have sat/b per default selected with a given amount in the settings? Like we can fill in our own default fee per tx?

Next version.