with out knowing the airspeed
You are not interested in airspeed because measurements are being taken from ground impact references (prop slash marks) which relate to GS.
The last data point gives a GS of 108 knots, which equals,
108*6080/60 ft/min = 10944
Four bladed prop - distance over five (one RPM) consecutive blade strikes I measure at 6.9 feet ie one complete prop rotation
Prop RPM then equals 10944/6.9 = 1,586 RPM
I used a mixture of Google Earth and the dimensions between ridges of the roof cladding to work numbers.
Connedrod, quite correct that you have no idea of the power being produced, though touchdown was with yaw about 25° and a 6° descent (rough figures).