I would let him out as planned.
You should stay with him, the first few times he won't go far. If you notice any Fox pooh pick it up and wash it down.
I have two cockers, large garden with Foxes playing overnight - plenty of Fox pooh.
I do my usual walk around in the morning, picking any Fox pooh up and washing it down.
Go as you mean to go on, the business is outside.
Currently have a 16 week cocker and a 16 mth cocker!
Have Fun!