Looking at the map again, I see I won't be able to truly start building my Lorelei team until I get to Fuchsia City. That's four badges in.
I can't even expedite it with Go Park, because that's in Fuchsia City too. I'm gonna have to find an interesting way around this to avoid making this a boring playthrough. Luckily, I can get Shellder before I reach Celadon, so if I can get my hands on a Water Stone, I'll be on the right track towards having this Ice team.
EDIT: If Let's GO is truly following the guise of Yellow, I could obtain a Water Stone from the Celedon Department Store, and I believe Celedon, along with Saffron and Lavender Town, is accessible prior to obtaining the Vermilion City gym badge. If this is the case, I just might be able to get a head start on making my Lorelei team before reaching the third gym. All I gotta do is follow A LOT of steps:
1. Accumulate enough money to purchase a Water Stone.
2. Go to Celedon City and purchase the Water Stone. AVOID ALL TRAINERS
3. Reach Lavender Town and obtain the Super Rod from the Fishing Guru. AVOID ALL TRAINERS
4. Go to the dock in Vermillion City and use the Super Rod to catch a Shellder. AVOID ALL TRAINERS
5. Use the Water Stone to evolve Shellder.
6. Go to Route 12 and use Super Rod to catch a Slowpoke.
7. Use all remaining trainers to train Slowpoke and Cloyster.
8. Beat the crap out of Lt. Surge.
Of course, this is only possible if all of what I need that existed in Yellow also exists in Let's GO. I hope it all does.