A tenant stopped paying in February 2020, I got eviction order and waited legal time frame for writ of possession. 3 days before that, maratorium on evictions happened..

Vacant possession should be standard language.

Seller may say NO, but would accept $85,000 --- so that's good - you've reduced the price by $15,000, your trial offer was successful.The next step is Second Stage Negotiation, you've made an appointment, you got your comps, you have a fair idea of value - after inspecting the building you'll certainly find other deficiencies that you can negotiate for a lower price - at that time you make an offer that suits you.Pull out your Skinny Contract of sale and write it up - if the transaction is done right using the right clauses you should be able to control the building with right of possession and the right to market - now go find an assignee to flip your contract to.

I was told In 11 days I can file for possession of the property.

And, in most cases, even if they don't redeem, the original owner can retain possession of the property for at least a year after the tax sale until the tax deed buyer forecloses their redemption rights.  

Like they said, they cannot restrict you reasonable access during the inspection period (or you can definitely get an extension).Thoughts: less possessions and them fixing stuff is good for you.

They don't really care who you are or who owns the property.The rents will be apportioned at closing between you and the seller, and the day after you have possession, trot your happy self to the housing authority and do the paperwork.

When I took possession I told the tenant she had to go - she was mess anyway - and I told her I was going to renovate it.

You may have to buy the property unseen (so give yourself enough contingency)4) Some of the Auction properties come with possession at closing.

Typically whatever is owned by the seller becomes the buyers upon transfer so you immediately owned them upon sale unless stated otherwise so the renter should have no right of possession there.