Jamf Connect in a lab environment

My understanding is that Jamf Connect just gets you into the account and not much else (this is all I use it for regarding my district). If the device gets locked, that tells me 1 of 2 low hanging fruits: Either educate users to sign out when done with the device, or adjust the power settings to a more reasonable inactivity timer. 

Regarding your second point, Jamf Connect needs network access in order to work so what would be preventing the device from getting network access after a restart? Pushing a wifi profile could help with this. 

Issue 1: After Sleep, Only the Last User Can Log In

This is expected behavior in Jamf Connect, and it's a known limitation with how macOS handles the login window post-sleep.

When a Mac wakes from sleep, macOS presents a resume/credential screen for the last logged-in user — this is macOS-native behavior, not Jamf Connect behavior per se. The Jamf Connect IdP login window only fully presents on a cold boot or logout. The workaround you described (hovering to reveal Guest, then clicking back) is the documented informal workaround, but it's finicky.

Things to check/do:

• Confirm DisableScreenSaverLogin behavior in your Login Window config profile. If the profile is configured to show the list of users rather than username/password fields, this may be compounding the issue.
• In lab environments, the better long-term design pattern is to configure the machines so students log out rather than letting them sleep with an active session. A logout leaves the machine back at the full Jamf Connect IdP login window cleanly.
• Consider a login window profile key showInputFields (name/password fields vs. user list) — if you’re showing a user list, where "last user" lock-in is more pronounced.

There is no clean "always show Google IdP login on wake" setting documented so I think your best bet is to rethink the session workflow (logout instead of sleep).

For the second issue, what macOS version and Jamf Connect version are these labs running, and are these MacBook Neo/M4 devices or Intel/earlier Apple Silicon?

So you might be able to deploy a profile from Jamf Pro to those macs that signs users out after a certain period of inactivity. In Jamf School i see the options Under “Login Window” when creating a profile. I would also set the mac to not sleep unless you need it to so that way its still connecting back to Jamf and getting profile updates and such. 

You can also set the machines to auto restart as well. You can find this in a profile under “Energy Saver”. I have our mac mini lab set to restart every morning around 6am so they are ready to go and on the Google Login page.