Let's jump back to the beginning. It looks like your Pi-hole does not see individual IPs on client requests, but only sees the IP of the router or WAP. If this is the case, then you will need to change this so you can see individual client IPs.
If this is not the case, then we need to verify that those clients are actually using Pi-hole, thus the request for the nslookup commands. Without a terminal, you can still load a web page on the client while tailing the Pi-hole log. If you don't see a burst of activity in the log tail while the client loads a page, that client isn't using Pi-hole.