Hi j4bz, there are different answers:
in ePO where can I see a message saying something like "all antivirus databases are updating" an shows the date for each workstation?
You can use the "VSE: DAT Deployment" query inside ePO; this will tell you te deployed DAT into your computers.
can I block a work station from the ePO console
Not as far as i know, you can use drive encryption so the user won't be able to log into the machine without proper permissions but the computer must be connected to ePO so it can get the "revoke permissions" policy but there's no "BLOCK" button.
there's some product to add that says if one machine have all Windows updates or outdate and it can be add to ePO console
Perhaps this can ve covered by Vulnerability Manager, maybe someone that has used it can tell more