For the DNS issue check the following setting
Wireless > Configure > Firewall and Traffic Shaping
Is the rule set to Deny All to local LAN which i assume is where your DNS servers are. Either change to Allow or add a rule to allow DNS Traffic

Darren OConnor | doconnor@resalire.co.uk
https://www.linkedin.com/in/darrenoconnor/
I'm not an employee of Cisco/Meraki. My posts are based on Meraki best practice and what has worked for me in the field.