I may be the odd one out in this but....
I would be trying to help her sell by keeping things quiet, tidy and looking good.
The sooner she sells the sooner all the neighbors will have relief.
I agree 7 days is not enough time to make a change.
It does look like the most logical thing is to rehome this group and then work on getting them legalized.
In many places including here if a neighbors pet comes on my property it is only legal to trap and call animal control.
Guaranteed anyone putting nasty greasy stuff for my pets to eat (on the property line or in my yard) will definitely be caught in camera and prosecuted/sued/fined/jailed to the...
Most of those things if not all are illegal. :hmm
Personally I would keep it all 100% legal.
I definitely would NOT ever be messing with anyone else's animals.
Fertilizer dumping on another's lawn is vandalism.....and could be getting caught on camera.