Whoops, missed the second part. Will address that below.
Q2/3) On a small scale, yes. However, it doesn't work for any version of Internet Explorer on Windows XP; there's also some limits on the number of virtual hosts that work well on a single server. You'd also have to buy a certificate for lists.yourdomain.com — the normal certificate is only good for the bare domain and "www". As a result of this, we haven't committed the engineering time to get these working under SSL yet.
As far as Mailbox Manager goes — that's an older app in our system; it's not up to our current standards. We plan to fix it up soon.