Best Team for Pokémon Leaf Green/Fire Red?

Just got the leaf green/fire red ROMs on my phone, forgot how good these games are... Just started leaf green and so far my team is Wartortle and Nidorina...

Just wondering what people think the best team is stat wise building up to the elite four? I generally don't play with the legendary ones, and there are obviously a few very high stat ones like Dragonite but I just can't be bothered to grind with Dratini late into the game... So what Pokémon can be picked up relatively early in the game and become strong later?

Also, I'm assuming not... But is there any way to get Pokémon that would usually only be available through trade when playing on ROMs? For example, Gengar, Alakazam, Machamp and Golem?

Thanks! Look forward to hearing about some teams!