I set up my business to be as automated as possible by doing online rent collection, setting all my leases to expire at the same time (yea it sucks when I have 3-4 turnovers at once but since they all expire at the same time I only have to do it once a year)  I also figured out what my time was worth and hired out things that were not worth my time. 

I imagine there are 3 possible points 1) day of sale presenting receipt for 20%  2) once the 10 day right of redemption has expired  or 3) when presented with sheriff's deed.  

The rent could only be raised by the amount of yearly CPI (from 4 months before lease expiration).

She is paying $1225, but her lease expires this month. 

Personally I would do a cash out refi or HELOC while your tenant is in place, remodel the kitchen and baths as soon as their lease expires, and then give it a go as an STR. 

If a property already has flood insurance on it, you want to make sure the seller doesn't let it expire or cancel it so that you can assume it.

Just waiting for the tenants lease to expire.

I have a tenant whose lease expires in May.

The leases expired end of May. 

Do I sign a addendum with the new rent increase without giving a 45 day notice or do I have to give a 45 day notice since the lease says once its expired it goes to month to month.