Pretty much what it says on the tin, I'm afraid. Are there any rules regarding non-humans taking variant multiclass? Obviously the animal would need a passably human intelligence score, but are there any other requirements one would have to meet? What might be the possible implications?
I am also curious about the same issue in regard to familiars, although I recognize the issue of whether familiars gain feats appropriate to their hit die is a matter for some debate. I will say only that I have always allowed familiars to benefit from feats in my own campaigns.
The most obvious hangup I can think of, off the bat, would be the issue of a familiar gaining the Wizard VMC and getting its own familiar... That could certainly lead to problems.
Well, animal companions and familiars can't take levels in classes. Instead, so long as it is an animal companion or familiar it follows the normal progression for what it is.
Cohorts can take levels in classes. Since VMC is an optional rule you would have to check with your DM if a cohort is allowed to use the VMC rules. In general I would assume that if PCs are allowed to use the VMC rules then it's probably ok for cohorts as well. But I could see a DM not allowing it since cohorts are "supposed to be weaker" than PCs.
Animal companions get feats, by RAW an animal companion could take the leadership feat and gain a cohort of it's own. I have a hard time imagining any DM allowing this though as it would rapidly become game breaking, since this is repeatable with the cohort taking leadership themselves and/or gaining an animal companion that takes it.
Are there any rules regarding non-humans taking variant multiclass? Obviously the animal would need a passably human intelligence score, are there any other requirements one would have to meet?
"With this system, each character can choose a secondary class at 1st level that she trains in throughout her career, without giving up levels in her primary class." PU pg. 88
Selecting a VMC is tied to the first character level, which requires a class level. No class level, no VMC. Everyting that has a class level can, theoretically, take a VMC.Note that an animal companion does not have a level, all the level dependent abilities are keyed of the master's level. Same with familiars, eidolons, or phantoms. Thus, none of these can take VMC.
An awakened animal companion, however, can take class levels (and according to the section in Animal Archive they actually tend to!), and thus could take a VMC as well.
But since VMC is a set of optional rules from Pathfinder Unchained, the real answer is whatever you or your GM want it to be. In this case, there are no difficulties in figuring out how it would work if you allowed it.
I agree with David knott, that there is very little left to the imagination when it comes to the implementation of VMC on an Animal Companion.
Replace feats with the specified class abilities. No problem.
While it's not technically VMC, and therefore it has no official rules regarding this use of it, I don't see a problem with it so long as the animal in question is capable of performing the abilities it gains through the quasi-VMC...
In fact, I rather like the idea.
So first off, the animal companion entry explicitly states that an animal companion can never obtain class levels. The only way around this is to awaken the animal companion which explicitly states that an awakened animal companion ceases to be an animal companion. The inability to obtain class levels is highly probable to result in most DMs ruling that VMC is off the table for animal companions.
Secondly, Familiars do not gain HD as you level, they get virtual HD equal to your own for the purpose of effects based on HD (meaning special abilities and spell effects). Their HP is based on your HP rather than HD because they are always at their minimum HD for a creature of their type. The lack of actual HD progression means they never gain any feats beyond what they start with unless granted by a class feature or archetype.
I'd really rather not debate that second part, please. Let's do try to stay on topic. I do apologize, but it's such a contentious issue at my table that I'm afraid I'm rather burnt out on the whole argument
I think I've made my decision. I'm going to allow the animal companion to take VMC fighter. I can't think of what it might harm, and as David Knott and VoodistMonk say, implementation isn't much of a problem. Thanks for your feedback, everyone.