The left one's head has a very similar shape to Celebi's. There looks like there are leaves on the end of it's tail which makes the idea of it being the grass type very convincing. However Flygon has a similar shape on it's tail and Flygon is Ground/Dragon.
It's possible that it could be the water type as it has a very slender body and wide tail end which would help it to swim, although the tail isn't rudder shaped, making it unlikely.
This one is standing upright. Most fire starters are able to stand upright, so this could also be the fire type.
The middle one looks quite similar to Turtwig. The things on it's head could be leaves, and it's tail could be a berry so also could be a grass type. The tail is similar to Maril's, hence it could have a similar purpose but I think this would be unlikely.
The right one looks very much like a beaver, small ears, flat tail, body shape. This is most likely to be the water type.
Like the left one, this one is also standing upright so it could be the fire starter.
Ricotez said:
Please let this not be another grass/fire/water trio... There are more holy triangles, like psychic/fight/dark.
Contrary to popular belief, Psy/Fight/Dark not actually a true triangle. Dark is immune to Psychic attacks. You could try Rock/Flying/Fight and I think there are others.