I think some of the siding may have also been damaged by snow or ice sliding down the others roof and probably into the side of my building.

I don't do all of it - I've paid for new windows to be installed, and new gas space heaters, but SO much stuff you can find out how to do on YouTube and just gives you more knowledge overall to prevent contractors from dicking you around too!

I'd give him the legal notice, and return his deposit (yes, it will be painful, but if you don't have proof, IMO it's a lost cause, not worth the hassle/stress) , and offer him a sliding scale, $400 if he moves out next week, $300 if he moves out in 2 weeks, $200 if 3 weeks, contingent that he cleans up the place too.  

We market the property at lower price and then discuss a sort of 'cost averaging' for that utility during lease signing.Here's another 'out of the box' idea - depending on your layout and climate - you may consider electric baseboard heat as a different option for heat, coupled with using window units for air....Jim

I wouldn't pay for an actual inspection until you have it under contract but you can offer to slide someone a few dollars if they will come out and do a walk through with you.

-Fix in the following order, some steps can be combined.    2.1 Foundation    2.2 Roof    2.3 Electrical    2.4 Plumbing    2.5 AC    2.6 Exterior Painting or Siding Work and Windows    2.7 Drywall, Texture Paint.    2.8 Flooring and any tile work.    2.9 Doors, Trims.    2.10 Install all fixtures.    2.11 Install or Refinish Kitchen Cabinets.List and SellRepeat

Consider you won't be paying water, landscaping/snow, windows, roofs, common areas separately, but they will be in your HOA which you will have to recoup from the tenant.

Fourth, and most costly was the custom-built wood windows.

I installed a new hvac unit in my personal house, blew in 12 inches of insulation, added soffit vents 8 more of them, a ridge vent , and added storm windows at the recommendation of my hvac contractor. 

They would be better off dropping the price to $299 which would put the property in an MLS "up to $300K" search window for buyers.