Transfer to congested server

[MistakeNot]

For month waiting for transfer to reopen, just to see that Cerberus now out of the list and marked as congested. So, is this mark permanent, or after few hours/days i finally can transfer myself to friends?

Semi-permanent. Servers marked "Congested" will stay that way until SE decides to change the status. Changes in server status always happens together with server maintenance, and will be accompanied by a message on Lodestone and in the launcher about changes in Congested/Preferred worlds.
So no point checking every few hours/days.