Unforunately, I am not very informed of the Poke Cup rentals, but quickly scanning through the available Pokemon on Serebii, that looks like your best best. Starmie iirc has a godly moveset in Pokecup, and most other Pokemon are fast, high special users which is great. Tauros and a Rock/Ground type is very effective in Gen 1 competitive, so you can't go wrong there. Overall, I think you should stick with that first team.
Pokemon speedrunner and chess player