Currently you can not remove students account entirely from CoSpaces Edu, you can only remove their account from your license plan. This will remove student from all classes of all teaches sharing this licence plan with you (their assignments in these classes will be removed as well), but will keep spaces in student’s “Free Play” intact.
Spaces they shared using “Share” button (if you allowed them to use “Sharing” option in “Account management”) will be intact as well.
Just to be on the safe side check that the links you have are either in
cospac.es domain (like
https://cospac.es/edu/egIH) or contain
/Universe/ in path (like
https://edu.cospaces.io/Universe/Space/v6RAcuBWzy98e4cHx8hw9k). If either of above is true, then you can still access those spaces after you remove students from your license plan.