Gosh! Sorry, I meant to reply much earlier. A bunch of these you listed have exclusivity that pretty much means will probably never be able to use a selector.
I’ll break down your list into three basic categories, Subscription, Native T2/T3, and Everything Else.
Subscription :
No regular selectors, good use of rank up tickets, some are very slowly farmable in Dimension Missions( Refresh the support character list).
Mephisto
Dazzler
Spider-Woman
Morbius
Yelena Belova: also purchasable through Black Widow legendary 2500 crystals
Rescue
Sabretooth
Electro
Jubilee
Juggernaut
Gambit
Sentinel
Namor
Baron Zemo
Mr Sinister
Slapstick
Kitty Pryde
Aero
Thane
Ikaris
–Mystique: crystal 2500
–Iceman: crystal 2500
–Adam Warlock: OLD WHALE 6600 crystals, desperately needs readjustment in EVERY way for the cost
Native T2/T3:
Selectors cannot be used. Most are manually built from 1* up when unlocked.
Gladiator: Native T2, epic quest ‘final’ unlock
Knull: Legendary Native T3- gooood luck lol
Sentry- Epic, Native T3
Molecule Man: Native T3, epic quest ‘final’ unlock
Doctor Doom: Native T2, Epic ‘final’ unlock
Silver Surfer: native T2, play Giant Boss Raid Galactus.
Everything Else:
Nova (RR): Epic deluxe package, then easily farmed
Invisible Woman: Epic deluxe package, then easily farmed
Moonstone: Epic deluxe package, then easily farmed
Negasonic: Danger Room, very hard to farm, must play DR a lot
Professor X: Danger Room, very hard to farm, must play DR a lot
Rachel Summers: Danger Room, very hard to farm, must play DR a lot
Abomination: Danger Room, very hard to farm, must play DR a lot
Scorpion: farmable
Ares: farmable
Sersi: not farmable, good selector choice, Shield Lab
Scream: not farmable, good selector choice, Shield Lab
Scarlet Spider: not farmable, good selector choice, Shield Lab
Kid Omega: Shield Lab, X-gene selector??
Phyla-Vell: very slow farm, so good selector choice (and rank up tickets)
Daken: very slow farm, need x-gene selector IF it works (very good rank-up ticket choice)
Final Verdict:
Phyla-Vell is great to help speed along Epic quest requirements. Serves as a support character.
Daken also speeds Epic quest requirements. Fan Favourite.
Sersi, Scream, Scarlet Spider, Kid Omega would be my next choices with Sersi of these 6 probably being the most powerful and future worthy (MCU Eternals later this year) of the group.
Sorry for the wall, hope this helps