I am minimally looking to create a LLC for each flip and move the flip to an S Corp should I decide to the hold the property long term. 

Get the education you need so you can minimize the mistakes that are part of any business.

I would manage the 3 other units myself, cap ex and repairs should be minimal since it’s new construction.

I've seen many a person waste weeks, if not months, trying to do an undoable deal.

No do not waste the money on a second heating system.

This helped me minimize exposure. 

A family member has offered to partner and bring 15-20K as a down payment, but in the Houston market I'm not sure that will be enough down to convince any lenders.Is there any point in investing the time to find an investor friendly lender, or would I simply be wasting both parties time trying to pull off the impossible, applying for a low money down loan with okay credit and poor personal finances?

I agree it's a lot of money, and if you don't use the knowledge and network, it would be a complete waste of money, but if you get to work and work the system, it can massively accelerate your growth. 

IF you do your research and you aren't just wasting their time--Find a structural house mover and go from there.

Renters waste utilities when they are 'free'.