The home is in good condition from the upgrades he made and he's painting the interior next week before allowing it to be viewed.  

If the Architect wants $7500 to draw up plans and attend 2 meetings/walk thrus through the project, and an interior designer wants $5000 to do their design, finish choices etc...

I recommend an interior and exterior paint within the next year."

The replacement windows are installed from the interior, they but to the exterior trim/brickmold and then attach.

Do the interior renovations as they become vacant like you mentioned. 

I say it's apparently nice because he didn't want to let us see the inside, but the outside is in great shape and one of the tenants told us he's been inside and it's "gorgeous and huge" with no interior walls. 

Knowing whether you can get that depends on your exact location, the aesthetics of your interior, whether there's parking, and the other amenities in your building. 

He says he has 200k in it with a 30k roof 5 years ago plus some interior renovation. 

Just measure the exterior walls and draw some interior walls with minimal dimensions.

He said that I am responsible for interior piping that will extend from the current meter location to the other side of the house.