You have to wait 2 years to apply for a deed. 2018 certificate was probably purchased in June 2019 so if you acquire this certificate you will be able to apply for a tax deed on April 1, 2021. you will have to redeem other taxes. Like 2019 and 2020. So add two more years of taxes to your investment. Once you apply for a tax deed your interest will be 18% annual on all the money you layout until the tax sale.
It is cheaper to foreclose by tax deed then filing an HOA foreclosure . Tax deed fees are minimal and you will be under $1,000 in fees.
Once all parties are notified (including all current lien holders), the sale will be scheduled and it is the highest bidder that will get the title to the property. So for you to get it you will need to bid everyone out. The good thing is that mortgage and HOA fees will be wiped out but you will still have to deal with your family squatters and go through lawful eviction.
Now you have 3 options for the title to become marketable:
1. Wait 4 years for the title to become marketable. You can just seat and wait, rent out the property, use, do anything but sell it since title isn't marketable yet.
2. You can file a quiet title action which normally runs around $2,500 with filing fees. With this action all lien holders will be notified again that you acquired this property by tax deed and they will need to respond within X number of days. After you get final judgement you title is marketable. All process should not take more then 5 months.
Options 3. File for title certification (clear to sell is one of them) usually cost about the same as quiet title. It's a 60 to 90 day process.
So there you go entire process on one page.