CP line will take lesser moves on a 2x2x2, because no DL edge. I’d estimate 2-3 moves.2x2 Method:
CPLine - Like Briggs and YruRU. This usually takes around 3-4 moves on 3x3, so it should be the same on 2x2
CO - Orient the Corners using <R, U>. Can usually be solved in 5ish moves
Solved - Solve a layer using <R2, U>. Most cases are 4-movers, with one being 6 and the worst being 9. This step can be executed really fast
Should average around 12 HTM, and almost all of it is either R U or R2 U
This could also be adapted for 2x2x3 by doing CPLine, Layer(also solving top layer), E-layer. CPLine is similar to Faces, Layer is <R2, U> and faster than PBL, and E-Layer is the same(although it could be influenced during the layer, where you can't easily influence the E-layer normally). Should be around 15 HTM, same as WoowyBaby's method
The orientation would take quite a few moves, I’m unsure how you intend to do it in 5 moves. There are hundreds of cases, so given only RU moves, it kinda gives a lower bound of 5 moves on average at the very best. My guess for the average would be 7-8 moves. So that’s an average of closer to 15 HTM.
A cool method to show off; but not 1-lookable; and RU isn’t that great a moveset on 2x2x2 so certainly not spread (edit:speed) solving viable.