Hmm, OK this time I haven't looked at the other answers first. I think I am supposed to guess!

21 - Tigris
22 - Allen
23 - Luna, I think?
24 - Harry
25 - I know I've seen that cat before! Cirrus?
26 - Sorry kitty - I don't know!
27 - Lizzie
28 - Abycat's pot sitting kitty - Alice(?)
29 - Livvy/Basil?
30 - Micah