The big play for tax sale in CA is bare land in the high deserts and in the areas that have a lot of old recreational communities were lots never got built on.

And too play a little devils advocate..

Not sure if you were looking for a long-term hold on a two family, but it seems that was not playing out favorably for you. 

I'll let you know how it plays out.

I know its a longer play, but that would I consider if I was you:-)  

I’m just trying to play it as safe as possible considering it’s been vacant for so long and I have no idea the condition in which the previous owner left things.  

If they had not found the deal or participated at all, you would not owe them anything since it was off-market and they didn't play a role. 

Yes, having tenants pay ACH via a Tenant Portal software is best, but not all will cooperate and some will play games that result in NSF charges.We allow tenants to deposit cash/check/money order directly at our bank into our account.Many Class C & D tenants have challenges adapting to unfamiliar ways to pay and is often not worth the hassle (and possible evictions) to get them to change:(

Unless you bought RE a few years ago, created equity via successful BRRRR, flip, or do a combination you're just playing the appreciation game. 

An MTR play may work well for them.Long story short, it can be logical for a property owner to enter into a deal with an MTR operator.