Richard Mayhew is about 5'10, I would guess

Blue Sargent is just under 5 feet

Violet Liu is just over 5 feet

Trism bon Cavalish is about 6 feet

Penelope Garcia is 5'7"

I have way too many OC's to list here, but you could ask about them if you like.

BittyElphaba is a toddler, and is about 2 feet tall

Neville! I almost forgot Neville Longbottom. His height depends on what book we're talking about but, AdultNeville is listed on Google at 182c or 5'11"