Hi, my wife and I have a condo in Northern VA that is estimated to have about 40-50k in equity.

I have a house that currently has 350k in equity and has an NOI of $1,250 / month.

When appreciation increases your equity, it does so on a 1 to 1 basis, where every dollar of property value increase equals that same dollar in equity increase. 

The property currently holds about 25k in equity.

I have 3 rental property, they all have about 60-90k in equity.

So basically your dad is willing to give you about $20,000 in equity for a 70,000,00 loan he has left to pay on this house.Your out of state, house is rented, but as rental is not losing money and is covering it's own costs plus making hopefully some % of profit. 

I have approximately $93K combined in equity on both properties.

I like pre-con/new builds because it's easier to refinance and get the PMI off because of the built-in equity bump.I'm not sure how useful this is but just so share what I know as an individual investor (I'm not a licensed agent, but work very closely with a group of great agents who specialize in investment properties who are also investors themselves) who's fairly familiar with this market, here is a good real-life example. 

.- I bought a beat up home Sub2 in a great area 2 years ago and fixed it up while living in it and built up $200K in equity.

However, in my experience drama is more contagious than genital warts and should be avoided in equal measure.