@Sam AugustHELOC money is expensive money, so borrowing via a HELOC to buy real estate won't work.

So happy you're here.. what's your must-have feature in a potential property right now?

The bank will put a hold on them, so you can't just draw them out, so don't plan to need them for a while.This will cost you an appraisal on both properties to be performed by that lender. 

From what we can find, houses with piers in the neighborhood have largely had to go very deep (90-120 ft), so estimates from local foundation contractors are ranging from 70-130k.  

So, I've closed hundreds of loans for people. 

I would be willing to take an offer on the property in its current state so you could configure the construction any way you wish.

. - if you do this make sure it is well documented so that your eviction will not skip a beat if something goes wrong. 

So, would you suggest doing this and putting him in 1st position, once the home is completed have him removed from 1st?

I furnish and provide amenities that warrants this so I do a lot of work to find comps in this particular space.  

Not to say you can't make money at the cheap brokerages, some do, but rarely do you see the most dynamic, most successful agents who are killing it at small flat fee brokerages, so be careful there.Best wishes and good luck.