And how do you program a LNAV route to Penang without a valid FMC at that time?
With the other FMC that has exactly the same data, and which would have automatically "taken over" in the event the previously active FMC failed. Read the manual.
And you say that the most suitable airport is Penang, ie where MH370 flew to. So how do you propose to fly to Penang, manually towards the start of the ILS?
Tune the VPG VOR and turn towards it would be a start.
And how do you know when to descend without VNAV?
The 3-times table works pretty well.
And which checklist did you run first?
Given there'd be a gaping hole and a rapid decompression, an immediate emergency descent while completing the CABIN ALTITUDE checklist would be pretty good places to start.
And how long do you need until you’re ready?
As long as it takes, after descending to a safe altitude.
And what about the Left Autothrottle issue.
What about it? The thrust levers can be operated manually.
And what about the flight control, hydraulic, landing gear and electrical issue?
Sort them out after descending to a safe altitude.
And the navigation, communication problems.
There are no navigation issues (see above) and there are procedures for loss of communication.
And how did you inform the passengers?
After descending to a safe altitude, open the cockpit door, tell the crew what's happening and tell them to alert the passengers.
And how are you dealing with the overwhelming problems?
As above.
And have you lost any situational awareness?
Nope.
And why do you feel euphoric?
Because of the adrenaline rush caused by the foregoing.