I don't necessarily agree with you. the only "rare" type the main games used is Fire, as there often are lots of grass and water Pokemon available.New/old thought to bring up discussion, How should starters be typed? I personally think they should be Rare typing. Something not often seen or not at all seen, in order to add some kind of novelty to the starter.
On the topic of typing though, I'm always glad to see new combinations used in fangames. the old Grass/Water/Fire thing was getting a bit lame. even more so when the game just offers canon starters from the main games.
Seeing non-canon starters, or even types, is rather exciting to see, but most often the choices seem a bit weird. Like the Pokemon were different just for the sake of being different. I love seeing starter Pokemon that make thematic sense.
In terms of stats and balance... All pokemon's stats are editable, and though It would be weird having a Weedle being on par with a Bagon, I do think the argument that some Pokemon can't be put together because of their stats is a tad moot here.