- Is there another unrevealed antagonist?
Yes. Agatha and Hayward both walk a line of not really being a villain, and we get a Mephisto or Cthon teaser to close things out as Agatha shifts to mentoring Wanda.
- Does 'our' Vision exist at the end?
No. Regardless of what happens with the two current Visions, neither are the original. I think the two will fuse in some way and accept they're a new individual and not the original Vision. Wanda and Vis will end up going separate ways after the show.
- Do the kids exist at the end?
Yes. I think they'll tie into the reveal/teaser for Mephisto/Cthon, and their status at the end of the show will end up pushing Agatha and Wanda together and set up the next Dr Strange movie.
Nothing significant. He just runs back to Sword HQ pouting that he lost Vision.
Wanda mentor arch.
We never see him again after the show and he goes back to being a random MCU human.
- What happens to White Vision?
Fuses with the Wanda Vision, being a different entity and continuing to exist in the MCU as White Vision.
Witness protection dude that ends up not mattering at all or ever seen again in the MCU.
Nothing, she just played the character Wanda made her for that episode and Agatha played into it to maintain appearances.
- Does Doctor Strange Appear?
No.