Every property was a lesson about roofing/landlording/architecture/plumbing..

The problem is it’s a complete gut and rehab with holes In the roof.

Other items to look at include: hot water heater, plumbing, electrical, roof, siding, and the sub floor (look for soft spots).Hope that helps! 

Are there major repairs in the near future (eg new roof)? 

Roof appears to be OK though I wasn't able to get a complete roof inspection. 

What do I need to consider with the unpermitted roof?

This means that some are below, some are above to create that average.Your actual expenses will be determined by how long you hold the property not how old the property is.As a example you will need a new roof in about 10 - 12 years.

One suggested using spray foam on the underside of the attic walls (roof) and the other suggested blowing in cellulose over the floorboards of the attic.

If they say no then you don’t need to waste your tim racking your brain over it

don't forget those wonderful "special assessments" for new roofs, asphalt, front doors, etc) If you or an investor is going to buy this, the $204 costs me this.