Questions on UniFi Express

Can one use UniFi Express with a cloud key?

If one can use the UniFi Express with a cloud key, does the restriction of 4 devices increase?

Thanks inadvance

Not to my knowledge with their current firmware.

If you import the Express into an existing Unifi network the Express reverts to access point mode.

Thank you for all the help. I am looking at upgrading my father-inlaws network at his home from an unmarked ISP router to Unifi, this is why I am saking.