Mind you, the 'loths are among my favorite things in D&D. I like them. A LOT. I contributed to their lore with pieces in 3e, 4e, and their Pathfinder analogs, and for the first two of those I'd really like to see some of that move forward in 5e.
This article isn't bad, but it's very shallow and there are rather a number of things inexplicably left out:
What of the unique yugoloths other than Anthraxis, the so-called altraloths? Ed Bonny's work in 'Pox of the Planes' was very cool, and it's a shame to see it ignored or overlooked.
No mention of the elaborate 'loth backstory and history as heavily developed in 2e and continued in 3e? The 'loths aren't just mercenaries, they're the oldest of the standard fiends. No mention of the General of Gehenna as the first ultroloth, and the Heart of Darkness creation myth?
Colin McComb had some absolutely genius material on the 'loths, their motivations, origins, and ecology in 2e's Faces of Evil. I'm really not seeing much of that material appear here. If it's not being considered, it's unique enough to D&D, and well enough done that it's going to be a loss to the game as a whole if you don't.
No mention of the yugoloths' creators, the baernaloths? Daru Ib Shamiq? Harishek ap Thulkesh the Blind Clockmaker? The Demented?
No mention of the 'loths (and their creators') hands in creating the obyriths and the first denizens of baator prior to the arrival of Asmodeus and the first baatezu?
No mention of the intertwined creation mythology of the yugoloths and gehreleths? Each claiming to have been the first creations of the baernaloths collectively or the exiled baernaloth Apomps the Triple Aspected respectively? The utter mutual hatred between the two of them and their warring for control of Carceri? The gehreleths acting as living extensions of their creator -eyes, ears, hands, mouths-, mediated by the black triangles they were around their necks?
That stuff was amazing, and it was there for two editions of the game. You really truly need to take a look back at it if you intend to really do justice for the 'loths. You could always get someone who knows the background lore really obsessively well to freelance a bit.
And finally, Anthraxus was renamed Phraxus in late 3e FR and 4e because of the anthrax scare in the nws? Really? Seriously? That's hands down one of the lamest alterations of D&D lore ever. Words cannot describe how absolutely appalling that is. Please tell me that was a legal decision rather than a design team thing.