No sweat.As a real estate investor you need to maintain sufficient reserves for the unexpected.

On Airbnb, there is a 6-bed condo advertising that it sleeps 8 that is renting for $140/month that's closer to Mt.

I wouldn't lose any sleep about being a couple grand off on the rehab or closing costs, the real test is going to be when you attempt to refinance, assuming you can get the rehab completed. 

My plan is to acquire a portfolio of buy and hold properties sufficient to support my husband and me in our retirement (~20 yrs from now), as well as to create a legacy for our children.

For me, its not the swinging a hammer, working long hours after work, and sleeping on a mattress on dusty plywood that was going to hold me back.

I assume that I can take possession (change locks etc) and perform structural repairs sufficient to bring it back to habitable standards but my question is does that include sprucing up the property itself ie tree trimming grass cutting and the like to maintain neighborhood norms?

If that case, your W-2 withholding might be sufficient. if your AGI is less than 150k, you have to make lesser of 100% of the tax shown on your PY return  or90% of your tax for the current year. 

Each month's rent payment may consist of not only the rent, but an additional amount which can be applied toward the down payment on an already specified price.legal descriptionA property description, recognized by law, that is sufficient to locate and identify the property without oral testimony.lenderA term which can refer to the institution making the loan or to the individual representing the firm.

Like I said, I would stay put with this one - personally I sleep better with less debt.If it burns you so much that stale equity, then I would accelerate to max paying it down and then putting an LOC on top of P1 & P3.

No deal is worth you losing sleep over or being stressed about something you can't control.