All feature early on in the franchise, (not much of a fan myself) but the Bulbapedia list of Pokemon by National Pokedex Number helped, especially with #2.
This was really fun, and made me join the site just to post my answer and a couple of questions about this!
(PEAS - S) + CAH + CHOO = PEA-CAH-CHOO = Pikachu
BULB + AH + ? = BULB-AH-? = Can only be Bulbasaur. But I don't understand the third part?
(CHARCOAL - COAL) + (LIZARD - L) = CHAR-IZARD = Charizard
? + GLEE + PUFF/HUFF. Since there is no known PKMN ending in "huff", it must be Jigglypuff (JIG-GLEE-PUFF). But I still don't get the first part? Is it a jigsaw, meaning we should put "-SAW" in the rebus?
MAGIC + (CARPET - ET) = MAGIC-CARP = Magikarp. This one was really clever!