Many sellers asking ridiculously high prices to see who will bite.

Everyone is doing postcards, so you won't stand out, and regular folded letters just get tossed in the junk pile by default.Of course, this is all a moot point since you're operating in an incredibly specific (but high demand) niche.

The money comes from the HOA dues, but if the company mismanages the funds or has high overage and people not paying, the money in the account is soft which will make it harder for lenders to lend there.

If so, how high/low is it?

Are they the same quality, bed/ bath count etc.

@George Baal I would recommend taking out the HELOC to start but given the high variable interest rate, I would then consolidate that debt into a better financial vehicle.

Insurance is highly specified to the situation, individual, property, etc. 

Cost for real estate here is high, I’m sure there are deals to be found in and around the area.

(After selling a few, I may do another house plan or turn some into rentals)I’m hesitant to build any with materials being so high but I figure if they buy it before it’s built my risk is mitigated.

The potential risk of foundation movement and settling in the neighboring unit is high and they will be looking for compensation for any issues your underpinning job causes.