It seems that the gear was down.
A ground observer and the online flight recording link both seemed to indicate a very high approach speed.

Is it posssible that a frozen/ plugged or partially plugged pitot tube could have caused an excesive approach speed?

I've been flying for more than 25 years and the scariest event I ever had has a frozen static port in marginal weather.

GPS provides a ground speed that is a backup for the airspeed
indicator (accounting for winds)

You started the flight in the wee hours of the morning, you are tired, flying a routine
approach in reasonable weather are you doing all the proper cross checks?
It's clear that you should be, but it's also clear that something went very wrong with the end of this flight.
My guess is that it was a coupled approach and pilot just adjusted the throttles to maintain the indicated airspeed....

One other possiblity is that he landed long and was trying to go around and ran out of space.

Paul