It's extremely unlikely the starters are going to ever be transferable.
They're not tradeable between the 2 games for one, which already gives a massive hint at it.
An Eevee or Pikachu with access to those moves would also completely break VGC and BSS, as both would get access to their signature Z-moves which also add another layer of brokeness, and we know VGC is the only competitive that GF cares for.
I thus think that the new TMs are to be expected to be present in gen 8 in some form, either as tutor moves or actual TMs. What we cannot really predict is if move changes will. I don't think they will, cause some of them have been done for clarity or due to lack of mechanics (stronger 2 turn moves, Mega Drain basically taking Giga Drain place, etc).
But the new Teleport carrying over in gen 8 could indeed be interesting if that happens.
Not only that, you NEED the Starters to do their Secret Techniques. It's pretty clear the Starter Pikachu and Eevee are locked to these games, not just because they have absurdly powerful moves and viable stats.
At best in future games they could have an item, we'll call it the "Let's Go Cap", which can be given to any Pikachu and Eevee and it makes their stats resemble the Starter Pikachu & Eevee but have no Ability. Also they wouldn't be able to hold an item so no Light Ball or Eevium Z.
Also the Starter moves aren't going to carry over, they're too OP and only exist to make the Starter Pikachu and Eevee viable throughout the game. Now I wouldn't be opposed if they allowed Eevee to learn certain elemental moves via being bred from one of the Eeveelutions. Obviously I'm not suggesting anything powerful, but could be neat (especially for Z-Moves) if Eevee could get moves like Water Gun, Thunder Shock, Flame Charge, Confusion, Pursuit, Razor Leaf, Icy Wind, & Fairy Wind.
Anyway, there's just a few more things from Kaphotics:
An Out Of Time Mina Appears: So, yeah, as you saw either though Kaphotics tweets, the trainer data, or naturally encountering her playing the game yourself, Alola's future sole Poni Island Trial Captain Mina makes an appearance.
So, the only way it can make sense Mina is here is if she's 9 or even 8. While no specific amount of time is ever mentioned between Gen I and Gen VII, considering Red & Blue are kids in Gen I and adults in Gen VII we have to assume it's at least been 10 years. Canonically Red & Blue in Gen I are 11, so this would make them 21 in Gen VII. The issue here is that Trail Captains retire their title at 20, so only way Mina can be here and yet still a Trial Captain in Gen VII is if she's 9 or 8. Of course, they design her to look as old (or maybe even a bit older) then the player character who is assumably the same age as Red & Blue. So, yeah, not impossible but I feel they really stretched this cameo. "Or they just don't care about the timeline". If they're gonna include characters from other generations into the games they should. The Pokemon World Tournament in B2W2, while cool, annoyed me about that with the kid Gym Leaders and so does Wally in the Battle Tree. I'm just asking for them to take timeline into account and giving characters the appropriate appearance, that's all.
New Move Descriptions: So all the Eevee moves do indeed have an affect, and some are quite interesting. Going over the ones we didn't know about: Glitzy Glow (Psychic) puts up a Light Screen, Baddy Bad (Dark) puts up a Reflect, Sappy Seed (Grass) inflicts Leech Seed, Freezy Frost (Ice) is an attacking Haze, and Sparkly Swirl (Fairy) is an attacking Heal Bell. That's pretty interesting and maybe an idea they could explore with future moves having a % chance of activating certain effects only status moves do. Actually, I always thought Seed Bomb and Seed Flare should have a chance of inflicting Leech Seed, makes sense contextually to me. Out of all of them I'd say FF probably got the short end of the stick, I get that GF didn't want to have a 100% freezing move and Haze is a useful side effect, though compared to others it doesn't quite alter the course of the battle since main game trainers rarely use stat increasers/decreasers. Maybe having Freezy Frost decrease the target's Speed would have been more helpful, a more powerful Icy Wind pretty much.
And that's really it. Though with the game being out now I think I'll go back to hanging out on the main Let's Go thread. One of the commentary groups I watch are starting to do a playthrough of it and there's plenty of other miscellaneous videos being made of certain aspects such as easter eggs, walking Pokemon, and notably what Pokemon you can ride. :)