It was difficult trying to illustrate a male Alice, because young male fashion in the Victorian era (of which Alice's iconic blue dress comes from) is very unbecoming in the present day. Most children's clothing was pretty girly. The closest outfit that could make Alex look good was a waistcoat, cravat and knickerbockers. Alex is still as curious as Alice but has a more brash attitude.
The White Rabbit is rendered as a younger adult rather than the typical old gentleman. His clumsy, awkward and anxious character, as well as his smart outfit, makes him fun to draw.