I’ll do a couple other lineups that are more balanced.
All have Native American scenery
Woodlands Pack
. ABB
. NA River Otter
. Elk/Wapiti
. Virginia Opossum
. Common Garter Snake Exhibit
Plains Pack
. Black-footed Ferret
. Burrowing Owl
. Patagonian Mara
. Greater Rhea
. Grass Snake Exhibit
Forest Pack
. ABB
. Elk/Wapiti
. North American Porcupine
. Mallard
. Northern Flying Squirrel WTE
I like all of these ideas!
It will depend on what theme Frontier went with - Woodlands, Boreal, Tundra or even Taiga focusing only on NA animals, but I think the one that would almost certainly be in any of them would be the ABB. While not as highly requested as some other animals, I'd say it's almost without question North America's most iconic zoo species mammal not in the game as yet.
After that - high contenders - Muskox, Elk/Wapiti, Walrus, Canadian Lynx - between some highly requested animals and some easier to do animals I think 1 or 2 of any of these would decent chance to make it in.
Middle ground contenders - Wild Turkey, as America's second most iconic bird (and some may say most iconic). North American River Otter (almost put up one level but neither a group Frontier focuses on a lot), Black Footed Ferret (same family as the Otters but is a conservation icon hence why it's not in the group below this one) I think it's possible we may get 1 of this group, but no more than that.
Oddballs - Mallard, Virginia Possum, North American Porcupine, Arctic/Snowshoe Hare (or another Hare or Rabbit). Between new rigs, difficulty of rigs, I think these may be a little less likely but still, Frontier likes to throw in oddballs every now and again. There's also no denying a Lagomorph would be very recognizable and iconic of a wild animal, the bigger issue with it is that it's not an iconic zoo animal. Which is why discussion on them hadn't come until recently so late into the game, they're just not thought of as being in zoos.
So for the 4 habitat animals, if we generally agree the ABB is definitely taking a spot, the other three spots would be one from each of these three groups, or two High contenders and one of either the Middle Ground or Oddball groups. Though there's a chance Frontier would just go with the bigger names in general and include the ABB and all 3 of the High Contenders.
Assuming we get any of this at all of course.