It would be helpful to the new homeowner to have access to the working schedule from the previous owner (even if flex). And if the house is on the market, want to keep it looking nice.
So clearing out the schedule may not be the best choice.
Finally, depending on area watering regulations, the limited schedule might earn a citation.
Might make sense to keep the Internet or get one of the low cost hotspots I have seen mentioned here.
Can you transfer an account? I guess you could update the email. Maybe make a firstname.lastname@example.org and label the password on the device.
Is it possible to change wifi settings without starting over? I haven't tried that.