you are not, but you have a lot of experience with Atlas, also you are making campaign for hyrule conquest so I thought you might be interested, sorry.
a) You can copy paste groups of trees.
b) Yeah, guess that is missing from Atlas. Also don't think there is a ticket already, so suggest to file one.
c) Trigger scripts should run, suggest to load the cinema demo map and run it in atlas for a test, that certainly worked in the past. Maybe I'm missing something here.