Save until you can invest in a good area where you can get decent tenants, I didn't say good tenants but decent to lower the barrier of entry. 

Saying that i'm comfortable and realistic with this rehab estimate and hope to bring in the construction at a lower cost. 

If so, how do I go about negotiating a lower purchase price or seller's assist to get some additional funds to fix the mold.

Lower unit is where the owner lives or lived.

I understand townhouse/condos are more of cash flow plays (vs. appreciation) so wanted to get in at lower price to be cash flow positive...hence the recommendation ask.Specific community names would be appreciated...e.g. one I'm aware of is Meadowridge townhouses in Coppell.

In March of 2016, she refinanced to a 20 year mortgage at 3.5% because it was going to be our new primary home and we felt at the time that it made sense to expedite our payments and lock in a lower interest rate.

There are some asset-based lenders that do not keep this rule, but they have lower LTV ratios and require a greater percent down.Hope this helps.

Lower prices yields higher occupancy and vice versa. 

Any way to get those costs lower?

You may be able to get a cash-out refi mortgage at the price of the next house at a lower interest rate.