So far, Grayven's shtick has been "resource optimization" i.e. making sure pre-existing personnel, knowledge, technology, and resources are used to their fullest potential as well as having overlapping fields of synergy/collaboration so that the whole becomes greater than the sum of its parts.
Sure, this
sounds simple, but often the simplest sounding tasks prove to be the most difficult.
Don't forget about his connections to Cranius and UnCorp, trying to make transhumanism more mainstream and socially acceptable.
Semi-OT: I'd love it if Cranius allowed Grayven to awaken one or two Un-Men into Un-Gods just to see what'd happen. Cranius is all about throwing everything at the wall to see what sticks, and shouldn't be afraid to step outside his comfort zone and
embrace new possibilities. To paraphrase Mayuri Tsuchikuro from Bleach, "There is no such thing as perfection. To believe in perfection is to believe there is finite room for growth and evolution, which is tantamount to despair for a true scientist."
Does the Challenger Base currently have any wards or defensive enchantments? The problem with most headquarters is that they rely entirely on technology or entirely on magic, but rarely a combination of the two (see Doctor Doom).
Circe,
Jean, Dr. Robbins, and Sunset Shimmer would have a lot of team synergy due to their specialties complimenting each other, with Jade as the "co-dragon" and Miss Aname as the token brute/enforcer.
And Circe could be a surrogate 'cool aunt' for Lynne and possible role model.
=
P.S. I'd like it if someone in-universe pointed out that
all of Grayven's minions are female.
Wonder Woman:

(glare)
Grayven: "What?"
Wonder Woman: "
So you just happen to surround yourself with beautiful women?"
Grayven: "Ahhh, I can see how this might look a little misogynistic, but it just worked out this way. Honest!"
Circe:

"What's the matter? Feeling jealous?"
Wonder Woman:
OR
Jade:

"
What's this I hear about you building a harem?"
Grayven:

"
Honey, I can explain!!!"