It is a request and reimburse process to fund the whole renovation.

They inspect the work, then they reimburse me with money I have to pay back to them anyway?? 

It may state that the contract purchaser agrees to pay the RE taxes... and if they don't, the seller will pay and seek reimbursement. 

During the Redemption period you can do work on the property if it falls into the category as posted in the code which states that if the work done is to MAINTAIN, PRESERVE AND SAFEKEEP  the property you can be reimbursed for that as well including the 25% penalty fee. 

No automatic with tax lien sale, but there are strategies for gaining possession and improving the property, and getting reimbursed even if there is a redemption.

If someone else bid, then you will get reimbursed your fees.Tax certificate is NOT a way to get ownership of property in Florida.

Do you expect to reimburse your buyer if they find own you didn’t know about?

It is very doubtful you will get any of the security deposit reimbursed, and it was a mistake using it.

Multiple tenants want me to either reimburse for the hotel stay or reduce their rent for the following month.

You don't say whether you are using hard money or not, but know that hard money often works in arrears... you front the money, then they reimburse you.