I do see some talk on this list that bridges are more in need at the moment on balance. And that some of the new obfs/scramble/pt protocols could use some deployment testing and feedback.
As far as your proposed hoster, they do not seem to have flatly refused an exit. You may wish to propose to them actually running one under your suggested responsibly handling abuse tickets for them. And make sure you can fall back to non-exit or bridge with them without losing money if exit does not mutually work out. Better to know/talk these things with your provider beforehand. You can suggest that since tor is 'slow' a genuine impactive ddos is not really possible via tor, though of course feeble packeting that people will still complain about is. Show them your proposed exit policy, non smtp spam, etc.
3TB/mo is about 10Mbps so that is more the governing factor for billing than 100Mbps port link. You can apply various rate limits on tor or your system/port.
Tor itself does not need a fwd or rev fqdn to run. Though a rev entry can help to clue people like LEA in that the IP is in fact a tor node. And matching fwd/rev can help give users access to services that check that thing. If you do not have a domain to give, the host may be able to put the node name in theirs.
Good luck, thx.