I really like the first and the third ones!
It is amazing how the image changes with just a few color changes on the muzzle and the bg

Largely I was trying to decide whether I should remove the mask marks from the third or change them to be white like the second going forward. It's pretty clear from this side-by-side comparison that whatever I do, I shouldn't do the eyes the way I did them there (I think they're best on the first).

Hmmm... I'd vote for "leave the mask as it is", but if you really don't want to have it anymore (or not to have it blue), in my opinion no mask looks better than the white one.
But you're the artist and creator, so the last word is yours!

I just made another page of slight variants. White mask with dark eyes instead of blue eyes does look a little better, but yeah I'm still leaning towards white mask being the weakest design of the three.

The reason for the blue mask originally was just to balance out the colors I had for a naughty joke between myself and my mate (not wanting to put a sharp blue on only one place for the whole character and draw the eyes to notice it exclusively) and she liked the blue enough to change her color scheme to incorporate it. And I left the blue on the "clean" drawings because it had become part of the design.

Personally I like the versions with dark eyes like small critters have, because completely white-eyed version looks kinda scary to me, like a possessed creature.
White mask with dark eyes looks better than other options with it, but blue mask still looks better in my opinion ^^;

That design story is interesting and quite cute, I must say :)