Tara - Diva (because she is one, especially when it comes to eating *rolls eyes*)
Spirit - Pup Pup. When I train a little puppy, I usually call "Pup Pup" to get them to come to me or get their attention. It just stuck. Lately, we've been calling her "Woo Girl" (How I met your Mother). When she wants something (like a toy Tara has), she'll throw her head back & "Woo Woo" constantly.