Glad you got it working, the animation looks very good, played it 3 times, know what you mean about youtube allowing looping, I've a few clips on my page that could use that feature.
You're probably right about using another figure, if youre using P7 or 8 there is a pose conversion utility somewhere  in the menu tabs, hmm, you can tell from that I have not actually tried it so not sure how much help it may be.When I've had to do something similar, I made a file with both figures in it and copied and pasted frame from one to the other for similarly named elements which gaave me the bulk of the moves then just had "hand" key the extra parts.

One more thought, re walk designer crashing, your character's paws, what are they called in the hierarchy (internal name in the properties tab) you might try changing them to match a standard Poser figure's parts, save the renamed character in your library under a new name then select that cr2 for figure type in the walk designer, might be worth the effort if it works and you plan to use the character often.