First picture - Your f/ could be higher so both cats are in focus, but that could also be taken as intentionally short DOF. I go back and forth on that one. Also, the highlights (the sky) could stand to be toned down and the shadows (looking at the eyes, specifically) kicked up a notch.
Second and third pictures - It appears that both of you focal points are about 6" in front of the cats face so, because of the shallow DOF, they are out of focus. I'm assuming you pushed the shutter button half way down to lock the focus? The only problem with doing that is if you or your subject(s) move, the focal distance stay the same. That's the difficult part of shooting pets, the damn things never stay still.
Fourth picture - My only *tiny* complaint about this one is you could have cropped off the railing. I know it's very minor, but for some odd reason it's bugging me, but it's probably
just me.
One last thing - you can keep all your pictures in the same thread and rename the thread title whenever you feel like it
(at least I think you can rename) to keep everything together. Certainly isn't a requirement by any stretch.
Keep shooting!