If it is a secret, the would not tell you otherwise. That they bring up Jango and Boba at all is odd, as they have never been canon Mandos until potentially now.
Just looking at what they hinted at logically:
There is nothing that odd about it, to the general public those are the names most associated with the armor (there is cache in the name drop) yet they are letting you know we are moving on to someone
new.
There is not allot of value in a reveal hinting Fett, then revealing Fett.
There is not allot of value in hinting Fett, then surprise revealing not Fett it's someone new. As those expecting Fett would be pissed.
And implicitly saying someone new, then surprise it was Fett all along, they know would read stupid, after implicitly saying "after the sorries of Fett ...Another warrior emerges"
Just remember that's why they didn't hint Fett, they told you right off; this is After Fett- expect another warrior to emerge.
If you're later disappointed you think they
hinted Fett and it's not Fett
, they didn't, that's all on you.
They told you it wasn't, they moved on, you did not.
That said, I wouldn't mind however if an old horribly scarred individual shows up, as a somewhat ominous and recurring mentor figure.
D
