OK thanks to Swampert for the info. For future reference, here are all the Pokemon I was asked for and the correct answers:
"A round blue Pokemon with leaves growing on it's head."
Oddish
"A fire type Pokemon that's supposed to roar well."
Growlithe
"A Pokemon with large round eyes. The one that sings a lullaby with it's cute voice!"
Jigglypuff
"A hugely popular Pokemon that has a yellow body and bright red cheeks. I would love to see what it looks like before it evolves."
Pichu
"Blue and round, end of its tail works like a float. Its belly is white."
Marill