Same SSL for multiple domains
SSL certificates are tied to a particular domain, so no to #1.
2 works nicely as an option. A UCC/SAN certificate is just an SSL certificate with multiple valid domain names in it (called Subject Alternative Names). UCC/SAN is what I use for our Amazon AWS load balancer and it works nicely.
The only downside of such a certificate is that it shows the other domain names it's used for. If you have paranoid/picky clients this may be problematic.