On insurance side of things, there is a lot of variables.

It's probably going to mean paying points at closing, a high rate, and a serious pre-payment penalty (like 5 years). 

God forbid something happens and I either can't get rid of a tenant or can't find one, I would barely even be able to afford the mortgage

It worked out fine, though each time I got a little less than advertised interest rate (about 9% vs 10%) and I had to send a reminder email to to get my money back, but I did get it back.I ask about others' experience, because I'm still not 100% sure it's not a ponzi. 

It gives you a list of all the assumable mortgages in your area.  

I'm struggling a little bit on deciding the best agreement to make sure I can get some cash flow, payback the HELOC, and not drive the new mortgage up too much with the Refi out of the HELOC.

I really wanted to try finding a duplex that i could immediately rent out the lower half rather then buy a SFH and have a higher mortgage overallHow did you find this deal and how did you negotiate it?

Refinancing will change your mortgage rate, and if it’s worse than your current rate, it’s not worth it unless you’re getting a great deal.

What about rate and term refinancing?

Selling for $380k means an $80k taxable gain at long-term capital gains rates (0%, 15%, or 20%, depending on income).The $80k HELOC used for personal debts doesn’t affect your taxes.A 1031 exchange could defer taxes, but you’d need to reinvest in another investment property, not a home for your mom.