Welcome to the community and be ready for a huge amount of information at your finger tips.

Knowing this information, should I sell and take 300k(ish) to a bigger multifamily or apartment via 1031 exchange?

Your architect can create this for you.For hot water heaters, is there a lock on the door to that room?

Seller accepted my very low offer because the prior buyer walked away when the inspector informed him the septic was corroded.

So glad this place exists for folks like me to learn from you. ✨ looking for ideas on to  how to acquire an owner-occupied property  with 5% down by using a mortgage loan product to purchase , improve and  avoid mortgage insurance based on projected value?

This could potentially drive up the price on the subject property. 

I honestly believe that the cycle isn't finished and there are still good deals to be had, but you can determine that for yourself by doing some research. 

In our recent acquisition of a 34 SFR rental portfolio, we are exploring different approaches to handle this efficiently.

How do I properly analyze this property?

Remember when I said all it requires is to not get greedy; some would see this and obsess on being at "only" 40% ownership now and completely ignore the fact of how all that math plays out in this.