you mean Boba Fett? Arguably the more fearsome bounty hunter in the galaxy at this point, lol. The Fett Armor is Mandalorian make. Like you said its possible there are bounty hunters and warriors who returned to the root of Mand'alor, it just wouldn't be a big fanclub is all.
Well, Boba Fett doesn't become Mand'alor for a whiiiiile.
The problem is that there's really no information.
Last we see of Mandalore in The Clone Wars, there's a big battle going on between the Super Commandos and the Nite Owls, and... that's it. We never find out how that battle even ends. I mean, I think the implication is that the Nite Owls are pretty heavily outgunned, so they probably lost... but... yeah. We never really find out who wins, what happens to Mandalore.
It seems pretty likely that the New Mandalorian movement is done for, and the Death Watch have basically succeeded in bringing militarism back to Mandalore, but we never find out to what extent that happens.
Thankfully there IS lore regarding what they're like during the time of this rp... but the immediate state of Mandalore after the events of The Clone Wars requires a little embellishment. Looking over the wiki I suppose we can infer that the Mandalorians return to their warrior culture (biggest problem with TCW and Mandalorians, it pretty much gives them a case of cultural bipolar disorder: WAR WAR WAR, PEACE PEACE PACE, WAR WAR WAR!), and... presumably scatter from the nice neat concentrated, organized government of the New Mandalorians, back into the clan based culture they had in the past. They presumably remain without a particular leader until Spar shows up and becomes Mandalore the Resurrector... then their history pretty much continues on as the wiki establishes, eventually the Mandalorian Protectors are formed, allied with the CIS,
After the war, the Empire proceeds to offer mercenary contracts to the Mandalorians (which Kiden presumably begins to take part in, as she's coming into adulthood just around this time), however, as tensions between the Empire and Mandalorians increase, Kiden finds herself double-crossed by the Empire who decide to pay her with blaster bolts instead of credits. She shoots her way out and is on the run when she meets up with the crew and signs up xD
I figure she'd have signed on... 1 or 2 years prior to the start of the rp perhaps?
I just realized this is totally Kiden's themesong 8D