@Noroof
Yes to asking about finished state.
I would also ask for an estimated schedule of work so that you roughly know what is happening when. It will help you plan when you need to have decided on kitchen, lighting, radiators etc.
A copy of their insurances.
What time / days people will be working.
Do they need copy of keys.
Ask their planned end date - otherwise it can just keep on going.
Have you agreed the schedule of payments - do not pay anything up front.
Confirm the quote is 'all in' other that things they come across? Eg our foundations cost them more than they had quoted for, they had to take the hit on that as it was their misquote. But, we paid extra for unforseen stuff like electrics that were a mess once we removed the kitchen.
Access to the toilet - are they bringing one, or are you happy for the builders to use yours? We were having ours redone, so I was happy for them to use our downstairs one!
There are no stupid questions, our builder defo smirked at a couple of my stranger questions, but was very happy to answer everything!