Relatively minor note, but I just noticed Espeon and Umbreon on your post-E4 list of Pokemon. Eevee actually can not evolve into either of them in FRLG since there it does not keep track of time of day in any fashion. I'd like to push Staryu for top tier again. It's available at level 24 range immediately after Snorlax, which isn't bad at all. If you don't care for minimize you can evolve it immediately, and Starmie's stats are downright excellent for that point in the game. Its 100 SpAtk/115 speed are reasonably comparable to Kadabra's 120 SpAtk/105 speed which most people agree is pretty good even unevolved, and it has significantly better defenses to use Recover. It does decently against the next two gyms and slaughters the last two. The high speed means it can outrun Lance's dragons even at a level disadvantage and hopefully OHKO them with Ice Beam, it'll fair better than things like Blastoise, Lapras, Vaporeon, etc. that'll probably get outsped by the Dragonites at least. Gary's Tyranitar is the case where it'll fare worse then them, but Thunderbolt at least means they don't get a free ride, either. Starmie feels like a clearcut choice for best water in the second half of the game, especially the E4, and water's a pretty good type to have. It might well be the best for the whole game, depends on how much credit Squirtle gets for being available in the first half.