Thinking hermit/?... There's no tardis equivalent though...

Well, if we just generically go The Doctor, then my suggestion would be to buy all the trees, all the way up to the bottom row. (Somebody around here crunched the numbers if you're curious what budget you're looking at). However, in the interest of play-ability, why don't we go by Regeneration?

Doctor One - crotchety old man, more of a mentor than a man of action. I'd probably go Scholar

Doctor Two - Impish trickster with the power to obfuscate and befuddle people in authority. Call him a Charmer?

Doctor Three - Man of Action, well versed in Vunitian Aikido. Clearly he'd be a two tree character: Kung Fu Guy from the bounty Hunter book and Engineer: Scientist

Doctor Four - Brash braggart with a very big mouth (and tons of contempt for Authority). I'd go Politico with lots and lots of scathing tirade

Doctor Five - Boy, they don't have "Nice" as a template tree. He had some ability with the sword (holding his own against the Master), and a disarming smile. You know, I think I might go Gambler here - now, hear me out. I'll go Gambler for the Dice Manipulation talents, reflecting Five's ability to turn things around at the last moment (Warriors of the Deep, Revelation of the Daleks, Androzoni for examples)

Doctor Six - Wait, I want to change my earlier decision. Six would have the Scathing Tirade in spades, with the ability to cut his enemies (and friends, occasionally) down with his sharp tongue.

Doctor Seven - The goofy chessmaster with a decidedly dark streak about him. With his ability to play with your head like he does, I might go with an emotion manipulating Jedi tree like Shadow.

Doctor Eight - A man of adventure, even more so than Three (this is, taking into consideration all the Big Finish audios, too. If we go with just The Movie and Night of the Doctor, we dont have much to work with). I might go Archaeologist for eight.

The War Doctor - Soldier Heavy or Vanguard, without question

Doctor Nine - Now here's where we start getting tough to define. The Doctors from this point really didn't have one defining trait for the regeneration like the first eight did. They're harder to pigeonhole. Nine was defined mostly by being damaged from the Time War, so I might go back to Scientist with the Rebel Universal Spec.

Doctor Ten - Still damaged from the Time War, but much better at hiding it. More accurately, he seem to be running away from it, so I might lean towards Scout? You'll need some path-finding if you travel to the heat death of the universe and the year 5.5/Apple/26

Doctor Eleven - He's got an undercurrent of cold, hard steel under his usual Doctor-y self, so I might go Martial, just for the Good Cop, Bad Cop talents.

Doctor Twelve - Back to scathing tirade again.

Scientist perhaps?

Dr. Who - Deus Ex Machina

He's been alive for so long and seen/done so much that there isn't anything he hasn't already dealt with in one way or another. Basically he's statless as he's a plot device.

Newt Scamander - Seeker/Hunter with some Force Specialization to cover the "magic".

Anything to replace his suitcase?

Even if just sorta kinda...

Utility belt goes part way