We do not provide vagrant images or scripts.
Yes, I think so too.
The CE supports ActiveSync.
Yes, us too. On the UCS, however, we do NOT offer the CE version. We use the UCS as a substructure for customers who want to have a mail server with them and want to user other services/applications together.
However, for some time now we have also been offering a mail server for later installation:
I would say just go for it.
Install a Debian server (only with SSH) and then install EGroupware:
And maybe still read:
The 21.1 could in the next few days 
Stefan