Hmm. I still don't get why Expanded in that case though. As amazing as Computer Search is, it won't increase the consistency of your deck enough to make up for playing in Expanded with effectively zero Expanded cards besides the Computer Search. There are so many more tools (I don't mean tool cards, I say "tool" in a general meaning) available in Expanded that you wouldn't be able to use in Standard, and your opponents can (and WILL) use them, putting you at a massive disadvantage. You really should just remove the Computer Search and play Standard.
I guess you'd have to remove the Brigette too, but if you're concerned with getting out you Cosmogs turn 1 Professor Elm could do the job too. You should up the number of Ultra Balls to 4 as well, since it's your ticket to get a Lele when stuck (and of course, it will also get you any other Pokemon you need).
I think 4 Mt. Coronet is overkill. I've tried in the past using 4 copies of my Stadium of choice, but it rarely ever makes a different. So long as you're smart about when you drop your Stadium card, 3 should be more than enough to keep stadium control for the entirety of the game. If you're really concerned with that, you could tech in 1 Lusamine to always have the choice to recover them (although tbh, I would only recommend using her in Expanded so that you can discard her whenever and then use her with VS Seekers. I almost never run a single copy of any Supporter in Standard because of the lack of VS Seeker). In that regard, you have the same problem with Acerola. No VS Seekers means you can only use her once, and only if you weren't forced to discard her earlier (because lets be honest, even if you have a Sightseer or something you should still discard your entire hand if you're stuck, because that single card you didn't draw could have been the one you needed).
You could consider taking 2 Field Blower instead of 1, even if you're using 3-4 Stadiums. Tool removal can make a big difference. And that's not to mention that if you're playing in Expanded you're bound to see Garbodors. Being completely ability locked means you lose your turn effectively. Now they don't even ability lock themselves anymore, because they're taking Klefki to keep the lock for the duration of your turn only. I used to take only 1 Field Blower on a lot of decks, specially on the more tight decks where I felt I needed the space that the Field Blower was taking up. But in the end, being able to remove tools twice is just too good.
If you want to stay in Expanded after all, you could consider using Shaymin-EX. It's basically a Lillie that doesn't use your supporter of the turn, so it helps a great deal with consistency. I suppose that your bench might be a bit cramped in this deck, but you can think about it.
I think you should be using Battle Compressors too though. You don't need 4 in a non discard heavy deck, but even using just 2 is really helpful. You can discard energies straight from the deck that you can attack with Solgaleo-GX promo, or bring to your hand with Mt. Coronet to attach from the hand. You can also discard things you don't need in that particular game (for example, you can discard the Karen if you think you won't need her, because it would be a dead draw otherwise). And of course, recovering Supporters via VS is a massive help. If in your first turn you have a Compressor and a Seeker, your Seeker basically reads now as "play any supporter you want straight from your deck", no need to drop a Lele.
You know, you REALLY should be using 4 VS Seekers. I cannot think of a more powerful consistency item in the game. It opens your options so much, and it makes discarding hands much less punishing because you can always recover any Supporters you lose. I think you've got it backwards with the Lele and VS Seekers. Tapu Lele-GX is single-use for certain; it's a very useful card, but I can't understand what you mean by "multiple use", because you literally just drop it on the bench for a supporter, once, and then it just sits there warming the bench. With VS Seeker, as soon as you've discarded (or used) a Supporter, from that point onward all of your VS Seekers will come online for the rest of the game. You can open the game with a Tapu Lele-GX to search for a draw Supporter, and from then on you can keep recycling the same supporter with Seekers without having to drop another Lele. Then there's the Battle Compressor combo, meaning that a VS Seeker can even save you from a bad hand on your first turn.
I'm sorry but there really is no excuse to not use VS Seeker in Expanded xd I understand your reasons, but I don't think you're right after all.