Best plugin combination for multi sites


I have a few questions regarding the use of Pro-Sites and other mutlisites plugins.

We would like to setup a service where we could generate wordpress sites for our clients and they could have a domain name and pay monthly for hosting support and everything included.

So here are my questions :
- Can we use your plugins with any other wordpress themes (even our owns) ?
- Can upfront work with multisites functionality ? (On every pro sites we generate for instance) ?
- In our use case (generating independent websites for our clients), and we intend to make A LOT of them, what would be the recommended plugins : pro-sites, multi-domain, domain mapping, ... or a combination of those ?

Thanks very much,