I'm definitely interested. I did read your other post about shipping and are considering your area first. I'm willing to pay for shipping, that's not a problem. Just let me know when/if you can.
I'll just try to answer the questions. Bandensis live anywhere from 1 - 2 years, we don't know for sure as no one has really bred them before... til now (at least i think so). The longest i kept a bandensis for was about a year, but i got it when it was already an inch long.
Regarding keeping the cuttles in a 30 gal, It depends largely on the sex of the cuttles, if its a male and 2 females, they could co-exist but its likely they'll fight at some point of time. More than one male in a tank that small is going to result in a loss. The problem is that there is no obvious sexual dimorphism in cephalopods.