Are Alpha, Beta, and the Whisperers coming to the Walking Dead Soon?

It all started with a frame grab off the Walking Dead Season 7 trailer. This one below in fact. But mow there is a new rumor suggesting that The Whisperers could be coming to the Walking Dead sooner than expected.

Of course this is just speculation and there are a million ways that it could not be them. But the theory that the Whisperers could show up in Season 7 started with the ashy grey walkers above. When the Season 7 trailer was available, people started to wonder if these walkers were actually Whisperers. The Whisperers first appear in Walking Dead #130.
Now there is a casting call for a new “leader” that has people thinking Alpha is being cast. Alpha first appears in Walking Dead #132. There is also the Loot Crate Variant.
From Comicbook.com:

In an interesting turn of events, The Walking Dead is apparently casting for another leader-type role despite having actors for Rick, Gregory, Ezekiel, and Negan all in place as respective leaders to the only known upcoming communities.
According to The Spoiling Dead Fans, a casting call has gone out for a character by the name of Brion — a name never mentioned in The Walking Dead comic books. “Brion is an educated, poker-faced leader who has a superior air and does not let his/her motives be known,” the casting call’s description says.
The only comic book character this sounds like is Alpha who likely won’t be introduced until at least Season 8 (for those unfamiliar, Alpha is the female leader of the savage Whisperer group currently at war with Alexandria in recent issues). Furthering this possibility though, is more description consistent with the character. “Brionuses as few words as possible and keeps his/her emotions in check — we do see amusement, annoyance, displeasure,” the call reads. “Brion just doesn’t wear their emotions on their sleeve; he/she is confident, quiet, and chiefly concerned with how anything may benefit him/her and those he/she knows.”
The call is careful not to reveal a gender for the 30- to 40-year-old character but rules the role a recurring guest star for Season 7, with Episodes 7×10 and 7×12 as locks and 7×15 and 7×16 as possibilities. 

Of course they also provide one of the many outs:

Perhaps Brion will be the leader of the unnamed group Paul “Jesus” Monroe encountered in the comics. The character is called Magna and while she doesn’t match the descriptions quite as well as Alpha does, she would be a more likely candidate to be introduced in Season 7 than the leader of the creepy new group.
In the comics, Magna meshes into the Alexandria community with her group. She sounds like the safest bet for Brion unless Scott Gimple and company are looking to start seriously disregarding the source material by creating another community. Still, introducing Magna in Season 7 would mean the series covers a lot of ground in its 16 episodes or alters the timeline, seeing as the character was not introduced until issue #127 and season 6 left off in the midst of issue #100. 
Let’s not forget that Tara and Heath look to have encountered a new group out in the woods somewhere in Season 7. This Brion character could also be the leader of whoever the pair encountered despite not appearing in the already-filmed first half of the upcoming season.

 
Key Books to look for :
Walking Dead #130 First Whisperers
Walking Dead #132 First Alpha
Walking Dead #133 First Lydia
Walking Dead #154 First Beta
While this could be easily disproved, it is still a good time to grab these issues while they are fairly cheap, and before the official announcement is made.