Depending on location, what the foam is made out of (polyurethane is most common, I believe), other characteristics of the foam (R-value, whether it's water soluble, etc) and how difficult it is to install (are the cavities open or will the foam need to be injected through walls, etc) will determine the cost, but you're probably looking in the $2-5 per square foot (of cavity space) range.

My thoughts are that it is anything the builder may have installed that is not covered under the "product" category, which Item #2 covers.

DIY is not easy, mostly depends on how finicky your end user will be.

Not the most aesthetically pleasing but an option and more DIY friendly than metal railings.Good luck.

Install a crawlspace well or window well/ventcover, depending on size of vent.

My next project is to install laminate in the hallway and master bedroom and cover up the paper bag floor.

Then, Installed separate meters.

It's a little over half acre..Front 120, left side 170, right side 192 back 132..Seller seems motivated..The utilities are in place, but would need to install septic system...Any insight or questions of concern??

If the house does not have a working automatic sprinkler system which can be set to water automatically, you will need to either install one or at the very lease have soaker hoses put around the perimeter of the house and set up with an automatic timer. 

If it cannot be repaired as told by multiple trusted asphalt driveway installers I strongly suggest ripping it out and installing a new one that is up to local code and ordinances.