(I've learned that most people, and most things, in life, have a sales tag - it's just determining what the amount is).

that will determine is you need a lot of dwelling coverage or very little.As far as investing in condo I believe it is more b/c in order to make changes sometimes the condo assoc. has to approve anything and that can slow down your timeline. 

You can use that 50% as an estimate of what will be taken off a claim (Insurance Company Adjuster is the only one who can determine exact payout). 

Not sure of your mom's age, but while framing it would be good to determine locations / future locations for grab bars and throw a few extra studs in those spots.

That could also determine his comfort level in the area and if you'll want to start there.

This is my first time trying to determine cash flow on a new construction cabin we are considering.

You'll have to determine if the ROI at that range is sufficient. 

Before visiting the property we did our due diligence by looking for comparable properties on the MLS in order to understand if this was a good deal.Determining our offer price:We use the 70% rule to determine our offer price on any property.

I want to make sure I don't leave money on the table, how would I determine the list price given that it has the opportunity to generate rental income?

In the past I've just used Zillow to determine what fair rent is.