How best to decide on major CapEx expenses (ie, vinyl windows that may last 20 years but are cheap vs aluminum that may last 50 but are expensive)How best to handle what happens if/when one of us wants out of this in the future for some unforeseen reason?

When I did my first deal, we had some unforeseen events and were out of contract up till 36 hours till closing.

If that isn't the case, I'd assume 20-25% down.Next, if your ARV is $285K and you have $10K of fix up, I'd back the $10K out of purchase price and likely another buffer to allow for other unforeseen items that may come up post closing during the fix up process. 

Have a discussion with your tax professional about "unforeseen circumstances" regarding the sale of the residence. 

Investments should be made from a position of strength, which means having the financial ability to handle unforeseen expenses that will pop up.

If you can/ could occupy the finished home for a small amount of time it could potentially be sold tax free since the 121 exclusion (normally 2/5 years) has some exceptions for health reasons, unforeseen circumstances basically. 

If you are moving because of the work, health or unforeseen circumstances, you still get the partial exclusion. 

What unforeseen risks could I run into?

*Note: If the period of non-use was for 1) 2 years or less and due to a change in employment, a health condition, or other "unforeseen circumstance" described in Does Your Home Qualify for a Partial Exclusion of Gain?

Compared to D class, buying in a better (C class) area has many benefits such as less turn over, few unforeseen "emergencies" and problems.