UPDATE:
Berghia nudibranchs(4) got here a day early, but there was a delivery exception because of the heatwave and it came late in the afternoon!!
Cup temperature was 30.6C and the poor things definitely looked unwell.
I acclimated them as safely as I could following the instructions from Salty Underground, shut off my pumps, and placed them on the rock about 6 inches from the offending anemone.
Two of them disappeared into the rock immediately and the other two seemed 'stuck' together without moving so I set them an extra inch away in case they were needing a little private/alone time. ❤
I rose a little before 4am(sleep bores me) and wandered out to check my tank. The anemone was still open and defiant; effectively giving me 'the fingers'.
But!! Just an inch away was the hero of my story! A single berghia. I snapped off my little flashlight so that I didn't disturb it any more than I may have and carried on with a much needed cup of coffee.
30 minutes later, my curiosity got the better of me and I checked again. Berghia buddy is noshing to its heart's delight.
BAM!!
I'm not sure if the other little guys have made it and I'm hoping that my amphipod army didn't grab em. I hope that these super slugs can get all the aiptasia that I may not be able to see as well. I'm assuming that it's like that old pest control adage: For every one you see, there are 11 that you don't.
I'm completely bananas in pajamas and over the moon right now. Thanks again for helping me to identify this thing and for the guidance in its removal. You guys rock.
Lessons learned: Don't wait to handle something like this, check everything MUCH more carefully before adding it to my tank/quarantine, and pick livestock up at the delivery hub if I am able. Oh, and don't panic(thanks hitchhikers guide to the galaxy)!