2) Do you have sufficient cash reserves to pay for mortgage when you have vacancies or repairs and maintenance?

Your primary residence will not be taxed at the federal level, but possibly at the state level.

Does anyone know what would happen in Florida if you purchased a foreclosure property that has a federal tax lien filed after the lis pendens?

This is why banks like to see 6 months of reserves to weather the storms.

You also need money for reserves, so you can finish the job if you go over budget.For deals 1/2 this amount ($50k) purchase, I needed about $30k in cash ($10k down, $10 to start rehab, $10k reserves).Hope that clarifies and good luck!

Do you have cash reserves to pay the mortgage?

Hedge that risk by increasing your rehab budget.Lastly comes the monthly activity, 18% (6%/6%/6%) for reserves isn't as bad as I see other people account for it.

The most important element of a BRRRR is your cash reserves.

We do our renovations and refinance fairly fast and therefore typically self finance them (on a credit card that gets paid off each month from reserves). 

I will use my reserves to renovate the home and put tenants in right away.