I think it can be safely inferred that Orions are still not Federation members, because of these lines [
transcript]:
ORION [on viewscreen]: Enterprise, we demand that you cease your pursuit immediately. I must protest, as a representative of a neutral planet.
[...]
ORION: No, Captain. I can't trust that you won't report this incident to Starfleet. If you do, my planet will lose its neutrality and be subject to Federation retaliation.
If Orion were a Federation member, Orions collectively would probably not be "of a neutral planet" or "neutral." Reference regarding their neutrality was made in "The Pirates of Orion" to "Journey to Babel," and in that TOS episode they were also implied not to be Federation members, but rather one of the neutral parties besides the Federation.
The status of the Skorr in "Jihad" cannot be as safely inferred. I believe the implication is that they are not Federation members, especially because Spock says, "The warrior races of the Federation will rise up to battle the Skorr" [
transcript], which is how one would talk about an external threat, but even that line could still be read the other way.
Also I think that between the lines it's suggested in "The Survivor" that Vendor is not a Federation member, but as
@Christopher says, it's not stated definitively, and I would agree that it could be read either way. (
edit - My opinion about Vendor has been revised, see below.)