Honestly, to my eye, Track 1 and track 2 look like the same creature (other than the skull-beak, get to that in a moment). One is just rearing/roaring, and one is lumbering along or getting ready to charge. Other than the different colored, slightly differing style pummage (which easily would be possible for the same creature) and the "beaks", they look to be the same species. The same form/shape to their rear legs, the same "heavy up top" proportions, the same "reach"/formation of their "arms"/forelegs and "hands"/.paws/claws...almost identical heads/faces. Basically, they're either the same species or the brown one [track 1] is a forest variety and the grey-blue one [track 2] is a more polar or tundra or mountain dwelling variety. But their bodies basically look the same.
I picked track 1 because it's head looks like an owl. I know, it's simplistic and "traditional", but I thinik the Owlbear should have an owl's face...how much, how far it has feathers vs. fur and that sorta thing is all fairly optional/mutable. But I do not like the skull-"beak" of track 2. Maybe for something else/other creature...or an "undead" or "dire" version...I don't know. But seems to be a "bird-named" monster ought to have a beak..of the style of that bird...or close. If it has a hawk or eagle's beak...or even that of a snapping turtle, then why isn't it a "hawkbear" or a "turtlebear"?
I'll also agree with those who think the eyes should be larger...or perhaps, the coloring around the eyes/face should be giving more of an optical illusion of large round "owl eyes", even if the eyes in actuality, themselves, are normal "bear" size.
And I'll throw another 2 coppers on KM's assertion that bears are a bit more "bottom heavy." The samples, particularly track 2 look more "bulldog" even, than bear or gorilla.
BUT, as Klaus (I think it was) pointed out, are we looking for the owlbear to be that "magical weird mistake" of a bear and an owl [whether that is the "crazy mage got into the splicing magic, again!" or even if it is "naturally" occurring, like from a woodland that a "wild/chaos magic" storm passed through and melded all of the owls and bears together...and then they started mating...or something] OR are we looking at some horror of a species that just made its prey/victims think of it as, having traits/general appearance of, an owl and a bear? The two are not necessarily exclusive.
But it seems to me, and from what Jon said in the article, he does this too, to make the design of the creature "work", the origin story needs to be hammered down first and then designed from there. You need to look at the origins and how it the creature fitds into the "living world" of the game...to lay that subtle/unspoken layer of "realism" on the creature...like with human (or demihuman) looks and cultures, fashion and weapons, and/or [for beast-monsters, as opposed to tribal monsters/humanoids] furs and feathers, scales, beaks, tendrils, etc...
1) Where did they come from? 2) How do they hunt? 3) What do they use to hunt/harm/damage their prey? 4) How "common" are they? What are the chances or history of their interaction with normal/average folks?...and did that somehow contribute to their name? almost certainly...and then, of course, other things like the "ecology" side of it.
Are you going to find a "gaggle" of owlbears sharing a river/in the same hunting territory? Unlikely...except for mother and young together in the birthing season (or it's stipulated that owlbears really love salmon

) as both owls and bears are fairly solitary creatures. "Vulture-wolves" on the other hand, would almost certainly be found in "packs" or "flocks"...possibly in large numbers.
I like them both. I'd probably use them both as slightly different creatures. But for my "this is the image under the Owlbear entry" I'd go with track 1 OR the first one of the pencil/initial sketches.
--SD