Yes, this configuration is possible. sub1 - sub7.master.com will parked domains to master.com. Please ensure that Shape5 template stores its settings in database as native Joomla template. Including of custom.css depends on your template: if it allows you ...

Yes, this is possible.
m.mywebsite.com will be parked domain, so both sites will use same Joomla files and share VM data + Users.
Manual sent.

1. Possible, but all sites should use same Joomla installation, so you will be forced to use parked domains, but not hosted sub-domains. 2. Not possible, you can either share ALL articles, or not share them. But you can setup a specific category for each site and configure ...