TAWS turned off , Deteriorating Weather .
Re TWAS , The text says inhibited , not turned off , could have been U/S . whether this occurred before departure would be interesting to know. Normally in VFR it is not a MEL item since in VFR you are supposed to remain VMC and fly visual.clear of terrain . Deteriorating weather is a factor but not the cause, as, in VFR if you cannot maintain VMC you have to turn around ( easier said than done in the mountains, hence the issue. )
Reading that list I think points 5, 6 and 7 are closer to the actual cause.