An alternate way to 2nd clicking on a clip to paste attributes is to use Option + V. Here's how to mostly copy and paste attributes with minimal keyboard use. So far I can't find a way to navigate the paste attributes window without the mouse :(
01) Position the playhead on a clip. The up and down arrows work well for this.
02) Tap X to set the in and out points to just that clip.
03) Tap Option + A to hightlight that clip.
04) Command + C to copy.
05) Shift + Command + A to un-highlight the clip.
06) Move to the clip you want to paste the attributes to and repeat the above only at step 4 hit Option + V to paste attributes.
Because of subselections however. A subselection is where you have only part of a video or audio track selected as if you used the Range Selection tool (ggg) and if you have a subselection you won't be able to paste attributes.