I'd use the ceiling beams to drywall the ceiling. Closing it off would probably help you keep that heat in. You may be able to plywood the top and get yourself one of those drop down stairs people use for attics. Then you could use the space above for storage. As far as electric, the contractor would know better than me seeing as you are in a different country. As hard of a sell as it may be to your wife now, I'd go all out. Maybe there is a possibility for a small backup generator to protect in case of an outage, if it helps with the wife, say it's for the house as well as the garage. I think this is going to cost you a load one way or another but your place looks awesome so I'd keep it tight to follow suit. You've got a really nice property there bud, do it right the first time and you'll thank yourself later. If you don't you'll probably end up doing it again and cursing yourself for not bucking up the first time. Either way I'm curious how it will turn out, you've got the guts of an awesome fish room there.
