The moment it's a group, the dynamics bounce around too much and you can't talk to them. Every single person there would have to have a lot of respect for you, or they'll all be giving each-other side-eyes.
I would tackle it from the direction of caring and love and then more love, because they know how much care they have for pets and can extend from there. If they bring up consent, that usually means they've already heard these false arguments. In that case, what you're actually doing is fighting against pre-conceived notions instead of trying to explain something logically, so you've got to smack them out of it somehow. I'd talk about forced breeding and maybe cropping and docking, and get them to realize they actually don't care about consent. Once that's dispelled you can bring them back and talk about their methods of communication, and how they actually can consent when we want to listen to them.
You'll notice that we're working from our common ground. If they don't like the idea of zoophilia, it's because they think you don't hold the same values. And you probably won't hold the same values, but it's likely you've both got more in common than they thought. If they bring up pedophilia: again, it's about pre-conceived notions rather than logic. Assure them you hate it (and you'd better!), make sure you're both on solid footing there, and then explore how the adult animals aren't still developing and how they show their own independence.