Aside from answering those basic questions, you might want to include lore - as in, how this situation arose. A roleplay of this type with [i]normally[/i] non-sapient characters needs a general explanation because it raises many, many questions. Are the animals truly magical in some aspect or are they only capable of higher thought and speech? Were they uplifted by humans in the future to be more intelligent, probably for some specific role? Is this an alternate timeline wherein animals gained sentience and not just humans? Are there both "normal" non-sentient animals and sentient ones?

The other issue is where you are in time and its limits; is it the far flung past with primitive humans? Is it the conventional past, such as a "recorded" part of human history? Modern era? Or again the future, perhaps even a far flung or post apocalyptic future?

I always liked the idea of animal roleplays, given my love for the wild world, so I look forward to seeing what you have in mind.