Hanging an internal door on the other side in an older house

Ideally the joiner would of filled the gaps and the whole purpose of fitting a door is to make the door fit the existing door frame, so there shouldn't be any gaps.

Yes. The carpenter should fill/sand all old gaps and the door should be shaped to fit the frame with an equal space all the way round inbetween the door and frame.

The joiner should be able to fill and sand down where the hinges were. Depending on what standard of finish you wanted they could have offered you the option of replacing the wood completely. Because the door is for that frame it should still fit without any large gaps.

The carpenter should fill the gaps with a dutchman of fill and sand to a standard that suits the customer. The fitting of the door to and existing frame the door should have a nice margin all the way around the frame

If the Carpenter is fitting into the existing frame then normally he should use the same hinge recesses so that there is not repairing work needed however if you have asked him to do standard practice on hanging the door then he will do 150mm from the top of the door to the top of the hinge and 225mm from the bottom of the door to the bottom of the bottom hinge then one centre of them hinges on the door. Repairing the lining should be discussed before work commences so that the Carpenter can price for this. I hope this helps