First class upgrades have been said to start later this year, not on the 31st. No additional info has been announced and no start date for that. I'd imagine it will be very similar to how AA's own members are upgraded with the same upgrade windows in place. Probably will be behind AA elites but that's not clear yet, could go either way at this point based on what both airlines have said about first class upgrades. There's also the SWU type upgrade devices that have been said to happen later this year, but no info on those yet either.

MCE and other benefits have been said to start on the 31st. Though it's not impossible that it takes a few days for status info to propagate through the systems. No reason to think that hasn't already happened yet, just not something visible yet on our end.

This is all based on what both airlines have said. Yes anything can happen, but those are the facts at the moment with publicly available info they've given out.