Great questions. We rarely see this with flex, but since it is close to real time it can happen once in awhile.
Yes, roughly ~1 hour before the flex schedule runs we lookup weather data and compute whether or not it should run. We only try one time currently, but are rebuilding large parts of our system. One thing I want to do is starting 24 hours ahead of time, every hour check to see if it should run tomorrow (I would like to do the same thing with fixed schedules that have rain skip..), and continue to validate if it should run or skip right up till the time it is supposed to run. That is the future, for now we check once.
There are quite a few offline and reconnect events. I've PMed you date/times (MDT). Our support team [firstname.lastname@example.org] might have some tips/tricks on helping with offline events. This is as far as I can help.
Yes, since there were no recorded irrigation events, zone is still depleted, will water tomorrow.