What power does the seller have in a Subto?

[Alex Ng]

So I have someone who is foreclosing on a home and has agreed to a subto deal. I was wondering after the transaction, what power do they have left? I like to plan for the worst case scenario. Afterwards, do I have complete ownership of the property? It is in my ability to make payments or not. Can they still do something like cash out refinance or do a HELOC on his own? 30 years is a long time and you never know what the seller might do. I'm afraid they might one day put a HELOC on the property, take the money and run and I will be stuck carrying more debt. Is the seller still allowed to do that since their name is on the loan?

After a subject to, does the seller still have any part in the property anymore? Can they ever do anything that may sabotage the property?