Which came first?

[wckf92]

Straight leg front kick ? Maybe a little bend in the leg. How to do get more power with that? Sinking on the rear leg? A pre sink and rise back up ? Throwing the hip forward? Any and all of those? Other way? Or is it mainly speed?

Yes, generally straight, knee may or may not be bent a little, base leg should already be sunk, hip may shoot forward, and the upper body tilts back.