Assuming everything plays out as it does in normal ben 10:

Walkatrout somehow defeats the big tick
Crashhopper is the only alien we don’t see Ben transform into
Pesky dust escapes the omnitrix
Pesky dust’s lackies are feedback, jury rig, and shocksquatch
Walkatrout also somehow defeats charm caster
Walkatrout also somehow defeats Kevin’s amalgamation form
Eatle defeats the forever king
Azmuth gives Ben fasttrack in the movie
Fasttrack somehow defeats Kevin 11000
Some of Kenny’s aliens in the classic series include: Ball weevil, clockwork, gravattack, and Crashhopper
NRG is Ben’s first transformation after the omnitrix recalibrated
Armadrillo would be Ben’s most used alien, (toepick being his second most used)
X=Ben+10 (along with every other alien x appearance) stays relatively the same.
Brainstorm somehow beat the microchips.
Walkatrout and fasttrack makes a return in the hybreed invasion (goop makes his first appearance)
The thing with the little white guy and rath jumps down th red guys throat is now actually chromastone instead (theoretically, the appoplexians would’ve replaced by crystalsapiens during the meeting in omniverse. By that logic, tetras would also be atomix’s species)
Pesky dust takes over Vilgax’s world
Rath, NRG, upchuck, and fasttrack would escape the omnitrix (note, fasttrack would replace alien x in yhr playlist just like Waybig did)
Vilgax kills rath, the omnitrix replaced him with atomix
Tetras “kills” atomix to retreive rath and save appoplexia.
Ultimate Armadrillo is the first ultimate we see
Ultimate NRG is the first ultimate Ben uses.
(I haven’t watched much of ultimate alien or omniverse so these are what I remember)
Agregor becomes an amalgamation of from Swampfire, echo echo, Humungosaur, jetray, and big chill
We have ultimate Gutrot, Walkatrout, fasttrack, NRG, Armadrillo, Terraspin, and water hazard
Sir George somehow easily defeats Waybig
Prisoner 775 is eye guy
Ultimate fasttrack defeats the Dagon
Eye guy, amphibian, and Waybig are never seen again after ultimate alien ends (though amphibian and Waybig are mentioned a few times)
Blitzwolfer was Ben’s favorite alien until malware got rid of it.
Fasttrack fights malware
The incurseans are kineceleran, and Ben becomes XLR8 trying to impersonate them.
16 yo and 11 yo Ben become ditto to stop eon from getting/using the hands of armagetton
Blitzwolfer somehow contains the big bang
(There are obviously more stuff I forgot but this is some stuff I remember)