I'm willing to bet there's at least a couple of species that have it, it's just early on. It wouldn't surprise me if those who have had them are having too much fun playing the game to post about them too.
I'm surprised they'd be white and not pink, given that they're mostly hairless? Looks a little bit like Frontier just set colour to "no". A little disappointing.
Very cool that you already have some colour variations showing up, though! Looking forward to seeing what others turn up from this pack.
If the Google Image Search doesn't lie to me, those Babirusas are Albino and it's a big Difference. It was even the first Picture that appeared when I've googled Albino Babirusa so they could've gotten it right without needing to research for very long