Hi,
1. Regarding your questions, in general it is possible to use MSSQL as database since our underlying database layer also supports MSSQL but it is recommended
to use either Postgres or Mysql since all our tests work with those databases.. To make this work you need to install the PHP sqlsrv extension and use as driver sqlsrv
You should see a simple YAML format describing different apps, otherwise it is maybe a problem with your network.
best regards
Christoph