In Powershell, connect to your Live@edu service as normal and then use these commands. You might want to try it out in a test environment first. Also, this only hides the link in outlook.com not for other Live services.:

New-ManagementRole -Name MyOptions_Custom_NoPwdChg -Parent MyBaseOptions_DefaultMailboxPlan

Set-ManagementRoleEntry MyOptions_Custom_NoPwdChg\Set-Mailbox -Parameters Password -RemoveParameter

New-ManagementRoleAssignment -Name MyBaseOptions_DefaultMailboxPlan-RoleAssignmentPolicyNoPwdChg -Role Custom_NoPwdChg -Policy RoleAssignmentPolicy-DefaultMailboxPlan

Get-ManagementRoleAssignment -RoleAssignee RoleAssignmentPolicy-DefaultMailboxPlan | Set-ManagementRoleAssignment -Enabled:$True -confirm

Enable the MyBaseOptions_DefaultMailboxPlan-RoleAssignmentPolicy-NoPwdChg assignment.

Get-ManagementRoleAssignment -RoleAssignee RoleAssignmentPolicy-DefaultMailboxPlan | Set-ManagementRoleAssignment -Enabled:$False -confirm

Disable the MyBaseOptions_DefaultMailboxPlan-RoleAssignmentPolicy_DefaultMai assignment.

For GALDisabled, I followed the same steps, but based things on the GalDisabled plan:

New-ManagementRole –Name Custom_NoPasswordChangeGAL_Role -Parent MyBaseOptions_GalDisabledMailboxPlan

New-ManagementRoleAssignment -Name MyBaseOptions_GALDisabledMBXPlan-RoleAssignmentPolicyNoPwdChg -Role Custom_NoPasswordChangeGAL_Role -Policy RoleAssignmentPolicy-GALDisabledMailboxPlan