Well, you can use those monsters - you'll have to set them up as a regular Animation, though, with no blank frames. Center all stuff at (0,0), if you can. Then, in the Animation 2 tab, where it says Weapons, Poses, and Animation Type, click Animation Type.. you'll be able to set your animations to a normal battle animation.

Yes, battle animations can be one frame long, if you like the look of it.