Maybe this is obvious but we are sleepy so appreciate the help.

If I send a LOI (Letter of Intent) do I still need a representative like a RE Broker for residential properties? 

You likely won't get good tenants in the northeast. 39209 is the worst area, followed closely by 39213.

I would like to do a combination of both flips and rentals depending on what makes the most sense for the property location and needs.

Wanted to check in and make sure this got resolved for you.

I recognize that the CoC return is not as high as we'd like, but it does come with some built in equity (~$100,000)Details:- 3/2 Single family house (1487 sq ft) with a 1/1 ADU out back- Zipcode 78745- Purchase price: $469,900- Down payment: $50,000 plus CC (includes assignment fee)- Seller Finance $419,900 at 3.5% interest; 30 year amortization with a 15 year balloon- PITI $2744.02- Rental comps: $2667 for the 3/2; $1505 for the 1/1 - LTR according to BP (Total $4172)- Repairs needed - minimal, coat of paint and maybe swapping a window unit A/C for a mini split

Does anyone have any experience doing something like this?

Looking into this group also. 

Pay rent every month just like the other roommates do.

I can also point you to a ton of resources if you'd like to do your own research.