[Neus]

1) Mad Dullahans aren't usually magic users but I can see the need for a variety. Either way this was always my intention for the place.

2) I'd say it's medium sized. Probably about as big as Chaturanga's left sector, if I were going to map it. Excluding interiors, obviously.
2a) I always imagined it as having a town inside of the castle walls with the castle itself up some stone stairs at the north end of the town.
2b) Not off the top of my head.
2c) A decent amount, although its glory days were gone and many people sought opportunities elsewhere. More than Dormeho and Tannis, less than Cellsvich (by a large amount).

3) I'd prefer open use/free tilesets or 'from scratch' icons. opengameart.org has some, as do the existing map files in the editor. If you can find something which has been modified extensively enough, though, that's probably fine.

4) Up to you.
4a) It can be.