If enough water comes through, it could rot out the boards and the whole thing collapse.

You need dry weather to paint and usually above freezing (on the paint can).

However, there were some scuffs on the walls, the kitchen counters had some dried food on it and the floors were dirty. 

Yes, they take a little longer to dry clothes (which is why they are coupled with high-efficency / high-spin RPM washers), but use a fraction of the energy.

I would not require any structural improvements to the slab at this time, but I would recommend the owner maintain the following items in the future:Maintain grading around the foundation of the house per the attached specificationsKeep soil near the foundation walls moist during dry weatherExpect cracking in floor, and seal with flexible sealant when visibleThe proposed maintenance is designed to retain strength of the foundation.

It doesn't have heat or a/c but the electrical was updated 3 years ago and the owner/occupier of the property has made a few improvements including siding, paint, wood rot replacement, electrical.

As for investing our of area, I think you'll need a little more dry powder.

I don't think this is cut and dry but i typically try and see what might need to be done to occupy it, how strong the market is and what do you have to do to get a deal done because you don't want to pass an opportunity for paying a little on the upside but also don't want to overpay on something that has some question marks on it as well ( plus this is work you have to do which it would be good to be compensated for ) 

Our initial estimate suggested that it would take 6 months with 2-3 people working full time and subcontracting dry wallers and siding guys. 

Mold, rot, electrical, bad floor plan all can be fixed fairly quickly.