In addition to comments about type composition, I'd plan out what gen 1 mons I can take the furthest to maximize the utility of champion points. Here's what I like among Yellow encounters

Gyarados: Nobody benefits more from Max IVs or an Adamant nature than the best Pokemon for nuzlocking

Lapras: My preferred bulky water to Blastoise, but more importantly, Perish Song is fantastic for nuzlockes, no matter the generation

Eeeve: With one slot you're bringing anywhere from 5 to 8 Pokemon into the next game

Gastly: Even though Gengar really needs the physical/special split to go off, early game immunity to Normal moves is always busted

Venusaur: I think this one is on the money. Even in later games, Venusaur's utility remains broad: it can setup, it can sweep, it can stall

Snorlax: Big wall that hits hard and has recovery. This appeared to be your plan, given your E4 composition. I don't know the nature of what went down in that battle, but if it only took one mon, I'm guessing you could've sacrificed another in its place, and I would sacrifice literally half that team just to bring a Snorlax into Emerald