Re: 8/8ths q -
With a mayday call and 7700 squawk you would see a distress phase in place immediately, would mean phonecalls being made, SAR launched, positions noted, and possibly involving nearby aircraft immediately to gather whatever information may help.
With loss of comms in my neck of the woods you are looking at an uncertainty phase within 15 mins of the unanswered call, then upgrading the phase as the situation deteriorates.
I dare say though that if this occurred in my FIR where the loss of comms coincided with loss of radar contact (and if shown to be true) aircraft not maintaining level, then you would jump straight to an alert phase..