What you have obtained is a "Tax Lien Certificate" with a yearly interest rate that accumulates monthly, and it could be redeemed at any time by the owner via paying the County the amount of taxes owned + interest accrued during those months. if it is so then the county will pay you back your principal ($2800+ interest accrued)If after a Redemption period of one year, you have no received your investment back, then you contact the tax collector office to let them know that you want to apply for the deed of the property that you are holding the tax lien certificate.After application is completed, the Tax collector Office sends the application to the Clerck office for review and to schedule a Tax Deed Auction. 

interest accrues during this time and loan will be re-amortized to reflect such (offer good until 12/31). this applies to any existing loans as well as new.worth taking the loan for REI...Thoughts?

They'll likely just let the fines keep accruing, but by definition, a lien against a property means it can be foreclosed on to repay the lien.

You don't want to conduct rental activities under your flipping business umbrella.If you are planning to rehab then flip these properties,All of your costs are accrued as cost of goods sold and recognized in the year of sale. 

Another idea: I could put only 5% in for the down payment and not keep paying till 20% in order to keep the value accrued 100% profit. 

The CARES act allowed me to defer payments on this loan until 12/31 without penalty, though interest does still accrue.

Then 3 months before interest starts accruing I start paying it off, so I get roughly 12 months 0% interest loan of 10k with zero effect on my personal credit.  

It has about $60k left on the equity, it's 100k house, and is accruing 6.875% interest.

They need to pay off the loan by 8/22 or start accruing a $7.50 per diem thereafter, so we really want to help them get out now. 

This way you get a judgement and it accrues interest .