For the other question - you might have already read this?
MR devices running MR 32+ firmware, MX devices running MX 19+ firmware, MS devices running MS 17+ firmware and MS390/Catalyst devices running CS(17+) or IOS-XE 17.15+ firmware will use the username admin and the password will be the serial number (Cloud ID) of the device (upper case letters and dashes).
All devices running other firmware versions will use the serial number (Cloud ID) of the device (upper case letters and dashes) as the username with no password.
Using the Cisco Meraki Device Local Status Page
If you found this post helpful, please give it Kudos. If my answer solves your problem please click Accept as Solution so others can benefit from it.