You're a loooong time poster, so this first part isn't for you
Let's keep in mind that HHN Speculation doesn't follow the Oxford Dictionary definitions of words and there are three types of stuff on this forum:
1. Pull it out your @$$ Speculation - that's someone going to see John Wick 4, loving it, and saying "John Wick 4 would be perfect for HHN!" and setting the world on fire.
2a. Speculation based on past history - The event as a history with Blumhouse. M3gan was a huge hit for them. M3gan coming to HHN seems obvious....
2b. Uncomfirmed/Untrusted sources - The AMA when M3gan said "she" was looking forward to coming to HHN and everybody assumed that means not just attending the event, but partaking in it. That's more official then anything we usually get that early.
3. RUMORED houses. Stuff Rumored to be at the event, in the Legacy Dictionary, means something that has been hinted at by someone in the know. The highest probability/faith is put on those as they have the greatest chance of being correct. This is what causes issues with speculators, that Legacy tells them they're speculating but what they say aren't rumors. They seem like synonyms, but in his vocabulary, they are completely different.
So, M3gan was in the 2a, 2b and 3 categories. BUT, #3 is a crapshoot right now. With Universal Employees being told different IPs for the same houses, what was RUMORED (not speculated) before, is believed to not be RUMORED now.
M3gan is still speculated to be at the event. It makes sense, synergy, existing relationships, etc, etc, etc...PLUS someone somewhat affiliated with the IP said something on a Reditt AMA. However, the RUMORED aspect with It, Metallica, Deamon Slayer, etc all being RUMORED as they were passed on by insiders with track records of providing legit info, everything is up in the air right now. So M3gan was clearly RUMORED...and all rumors have to be disgarded at this point.
#3, the serious confirmations, have kinda been tossed for now until people start seeing props or costumes that are clearly related to an IP.
That's my $0.02 explanation based on what I think...but personally I'd be SHOCKED if M3gan isn't there. That's based on me using the #2 logic.