Remember, when the Seller signs the deed, you become the owner of the property and you would then have to turn around and give permission for the Seller (who at the time no longer owns the property) to make repairs.  

I think it’s a great idea to maximize your return but I don’t know if it is *technically* permissible.

He's not on the lease, but he was occupying the property with the knowledge and permission of his girlfriend, so he has rights.Start the eviction process.

The "ask for forgiveness rather than permission" strategy is beneficial to many cases, but township zoning departments is not one of them lol

I've read the HUD handbook for FHA loans, but can't discern if it is actually permissible.

They ran my background but did not ask permission nor did we ever discuss that.

This would be fine in theory for refinancing purposes but would likely limit your buying pool to those with commercial lending.Zoning is not in question in Los Angeles as they are "by right", meaning if they fit on the property, permission can't be denied due to recent legislation.For me, I ultimately decided against the build because my property was a pretty tight fit for the ADU units driving the cost up and a number of negative factors for the rest of the property made it iffy for me to begin with. 

Apart from the permissions, Do I need to consider something else ?

There are ways to cure the foreclosure (bringing mortgage current, buying from owner and giving them something for their equity, if any) but you have to work with the owners as their lenders can't talk to you without permission or assistance from the owners. 

I also want to include in my purchase agreement with the seller that we have the right to PRE-Market the property for Resale INCLUDING formally listing it for sale with their permission in MLS to that it will get greater exposure to more eyeballs.