Charmeleon level 18
Croconaw level 18
Beldum level 18
Bagon level 18
Gible level 18
Jolteon level 18
I cheated my party directly after getting my first pokemon at level 5 with their normal attacks at this level and trained them normally (I don't like training pokemon I won't use later and in Gen2 most of the Pokemon in the low-level-areas are weak in endgame-fights and I don't like fighting with only one Pokemon for so long ^^)
Bagon and Gible need a lot more EP than the other Pokemon (2 times the ep the starters needed) - because of this the level of my Pokemon is so low...