What seems like a downgrade to others, is an upgrade to me.

Imo, you bought the house, made some money because of equity and upgrades (assuming), so enjoy it.

3) If the latter, does anyone know what I can expect as far as a cost for insurance on property that is not fire code compliant, which will also be delivered vacant as I am doing upgrades to the units prior to re-renting?

I've spent a lot of money on upgrades that weren't necessarily needed, but the thought of someone even having a slight chance of getting injured on my property was worth doing the work.

Upgrades of 10k. 

The $300/yr is cheaper than removing the oil system and upgrading to NG.

So let's see that will mean I am down 10x $750 in rent. 5,000 in fire upgrades and who knows what in damage at the end.

I've concluded so far that our most profitable short term venture would be to make some upgrades, finish out the basement, and flip the property.

I’m sure this is a pretty general ROT and will depend on your market and what upgrades you’re doing?

I can paint the house, cut down a tree, upgrade the kitchen etc.After you have bought the property the second big choice you make is the resident.