It would all depend on limitations.
If working under the Spellcard system, only a couple Type-Moon characters would probably be capable of even fighting at all - notably Archer and his Unlimited Blade Works.
If not, it's... tough to say. It's been hinted that a few Touhou characters would be godly powerful if not playing by spellcard rules - as Spellcards have to be, in theory, dodgable, so many have to tone down their powers. Lets not forget things like Yuyuko's ability to instantly kill a person. But Type-Moon characters can be pretty bullshit ridiculous too.