That's how mine is set up and it works so far so go ahead and do it if you haven't yet, unless you got a reply from a someone saying that would cause an issue that I haven't spotted yet. The only issue that I think this setup can have is if lancache will only serve cached content to a dns request by the same ip (pihole) after a certain cooldown to prevent accidentally DOS attacking yourself in the case of accidentally making a dns loop or similar issue.
I wanted the lancache to use for WSUS for all computers since my home internet bandwidth is 6Mbps but not everyone in my house wants to use the pihole (they are crazy since with our internet speed using it helps a lot).
