They don't need to contest AP wise. Their abilities are sufficient which either support him or are dura negating like Shiva's AZ or Odin's Zantestsuken inflicting death on all of them, leaving Bartz to be able to simply petrify, time stop, or seal etc. whoever's left.
It is instant, it's just casted and he gets back up.
Transmutation's not the same thing as petrification. One can result in the other but not vice versa.
Why would invulnerability stop anything other than AP and isn't it from an item she actually has to use before hand? Also he has Libra which tells him how strong she is and what she does or doesn't resist.
Multiversal+ and looking at his profile, his regen is only Mid-High, which is nowehere near enough to regen from being in a void, not to mention everyone else including Adeline would be erased from being in the void
The only thing she really resists is transmutation. That said what are the reasons for death not working on some of the summons she uses?
He has more than one form of PN via Silence as well, which stops from using both magic and inherent abilities.