It's "canon".
Not cannon.
Here's a fun read: http://tvtropes.org/pmwiki/pmwiki.php/Main/Canon
So.. Hmmm.
Intelligent Deathclaws.
They're kinda extinct. [edit] (It depends if Goris against all odds found a deathclaw mother to mate with, and against all odds wasn't killed by it because he was "abnormal", and against all odds became the alpha male of the pack, and against all odds his "intelligent" gene is superior to the regular gene. If all of this went as planned then yes, Intelligent deathclaws could exist. With emphasis on "could".)
By the end of Fallout 2 all of them except Goris and Xarn were wiped out.
And since they were a creation of the Enclave which is now gone, there is no way to bring them back.
Goris and Xarn could of course breed with other deathclaws but the genes would eventually dumb down by each generation.
So they're kinda extinct.
So.
That's canon.
If they were to bring them back without giving a REALLY good and understandable explanation then it would be breaking "canon".
Wannamingos.
They're extinct.
Again, products of Enclave. (Or was it pre-war research?)
There is no way to bring them back, at all.
Their internal clocks simply stopped ticking and they all died out.
Bringing them back would be breaking "canon". (And no, the queen in Redding was killed, that's canon, and there was only one queen, so no "but there might have been another queen!")
[edit]
One problem though are the Talking Deathclaws.
They might have mutated in a different way from a different source allowing them to talk.
But still, Tactics is considered canon in some bits but I do not know where the Talking Deathclaws fit in.
I think
Styles would know more about them than me.