In this market, I tend to lean towards adding value to duplexes.

Any taxes not owed, a seller merely file a tax return with the state, just like any other tax returns filed for extra taxes a government has with held. 

This is interesting and I look forward to the feedback.But, I don't know if I want extra buoyancy in a hot tub?

Real estate investmnets are capital intensive and if you don't have extra money sitting around to make the emergency repair when it happens you'll find yourself in a terrible position. 

Is the finished basement SF added to the main SF to get a total SF which I then use as I normally would to get a per SF price or do I value the basement and main floor differently?

But I would charge the extra 3% to cover my costs.

The builder had a given us the paved yard, Granite kitchen top, washer and dryer at added value with no charge.

This money gets added onto the back of the loan kind of like a VA funding fee does. 

Since the repairs were two owners ago, I would think the town may be a little more lenient with you.With the new kitchen and bathroom, were they existing and just got renovated or were they added on?

Took an extra 6 weeks than planned,  but ultimately got it done.