The first two, technically the third as well.
I had a different aproach to the integration: letting phplist do most of the work.
General:- Provides single admin login to phplist/vb admincp ( i'll control this with vb admin perms before the mod goes 'gold')
- Syncs DB with phplist when a user registers, changes email or is deleted. Also updates confirmed status if user is moved into/outof vb email confirmation group.
- Provides mass import for users that already exist in vbulletin
- Provides admin mass subscribe to list with options the same as the create mailing list page in vb.
The only settings are settings for table prefixes.
My bounce handling i think is more inteligant as well; it lets phplist decide what to do with a bounce then unconfirms the user vb side that way you dont need to duplicate settings between vb and phplist. I expect this could be expanded to ban/delete users send them a pm or many other options. I'm awaiting feedback from the alpha testers.