I currently reside in Louisville, Ky.

I was thinking about renting out my primary residence which has taxes in 2017 for $5,900.

We don't have their new address but do have the one address they just stayed at for one month while they were supposedly waiting for their new rental and we also have the forwarding address they first gave for their parents home (their parents also resided in our rental with them and are being named in our claim as well).The total damages are high and it's a big house (almost 4k sqft & in excellent condition before the moved in).So long story, we need help on what to do about serving them with claims papers if they now live on base and we don't have their new address?

Non resident investors. 

I've been entertaining getting into the Detroit market, but will also be buying a primary residence in Norfolk in the Ocean View area.

Yes, I anticipate that any bidding with a party who intends to be the primary resident will exceed my "investor's budget". 

Or sell current home and roll equity into new primary residence?

We are FI-minded and although this will be our primary residence for many years, we have an *investment* mindset and would like someone with similar values and visions to help us decide on the best property. 

You should reach out to @Elliott Milek, he's a savvy cross border accountant who also invests in US real estate, and resides in the Ottawa area.    

My suggestion would be go on your overseas tour, save up , continue your education  and when you get back try and find a small multi (2-4) unit that you can house hack and rent our your current residence .