SpaceX Starship Users Guide 1.0 [pdf]
spacex.com
spacex.com
1) There doesn't seem to be anyway to dump heat. Half the reason had big doors that opened on its back was to allow it to expose radiators to space.
2) There doesn't seem to be solar panels either. Dragon (crew and cargo) deploy a set of panels from the "trunk" to provide shipboard power while in orbit. Where are those on Starship?
3) 100T to LEO in fully usable mode. So you can send a group of 10 - 15 people into orbit for maybe 2 or 3 days just for the price of fuel and human consumables? That is pretty amazing.
2) Different diagrams have shown it a bit differently. Usually they are shown coming out of the back of the rocket and then unfolding like a Peafowl. That's what probably those things between the Vac engines are.
But this is just me guessing.
3) Yes, this should be very possible.
There are so many new things possible its crazy. You could design a costume interior of the ship and launch that. Like a whole movie set and crew, or maybe almost like a sports stadium sort of thing for some new space boxing or whatever.
But if we have more then 100 tons to Orbit, it should start to be possible to have pretty big LEO hotels/stations for much less cost.