We are very much looking forward to the new challenges that we will encounter and we are very grateful for the vast amounts of knowledge and experience we are learning through BP forums, blogs, podcasts, as well as my Audible subscription. 

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.

So there are some flooded houses - gutted and ready for rehab, but I know that the vast majority of them are in flood risk areas ( I can double check with FEMA flood zone maps). 

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?

We've had hundreds of guests at our properties, and the vast majority are lovely folks who take great care of the property.

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.

I agree, but the vast majority of 401k plans don't allow direct investment into real estate.

They gave 30 days notice (actually 37), they agree to let me market the home during their final 30 days tenancy, they paid a termination fee equal to two months rent, and they remain responsible for rent and utilities until their termination date.If they leave and it still takes 60 days to find a new tenant, I've lost almost nothing.If they leave and I place a tenant right away, I made an extra two months of rent.I actually make more money on the vast majority of early terminations.

And if a buyer gets "cold feet" as was said, they need to use that as motivation and then find a valid reason to get out of the agreement, but "cold feet" as far as I understand the law as a layman, is not going to be sufficient.