As creator of the challenge...some clearification required, if you please.
Would you make it a rule that you have to play them at roughly the same pace, or would simply playing and winning each of 10 in order, without any other char played in between and without any losses qualify as a completed challenge?
And secondly, can one select different races for the classes chosen, or indeed select different classes than the ones you mentioned? I see you have a very wide range of classes, perhaps in my opinion missing either beastfighter or monk (instead of ranger or paladin, mabye). If a player is "might" rather than "magic"-oriented I guess he could choose 10 melee-type characters...and that feels wrongish. Ish. I also guess that starsign-scumming would be a bad thing, right?
A good idea for a challenge, win either by a lot of luck or patience or super skills. Or is that skillz. Anyway something for all of us.
I think I would play same-time-ishly. Grow each of them in VD/DD and see if they manage to get healing and/or grow to level X. Be a pain to finish 9 whole, and then die to a smashed head after walking 3 steps in first dungeon.
And I can't resist throwing burning-hands spellbooks on the fire here...what would you think about selecting the TH talent for this challenge? Did you? I know how I feel about this...
ADOM General's warning: Treasure Hunting causes slowness, frailty, terrible markmanship and is dangerous to your characters' health