Heroncloud: 9/10
I think this name is my favourite of the ones you listed. It has a nice flow, is fairly easy to say, and fits really, really well with the cat's personality.
Smokefang: 8/10
Again, this is a name that fits very well with the appearance and personality you've given. I have no intelligent advice to give here. XD
Appleheart: 6/10
I don't have any huge problem with this name- it sounds very nice- but I feel as though it isn't an excellent fit for this cat. I wouldn't think to name a pale ginger cat Apple; I'd go for more of a darker reddish ginger. (And personally, the prefix Apple has always seemed more feminine to me. But that's just me.) Additionally, for being described as haughty, the suffix -heart doesn't seem to sit right.
Kestrelclaw: 7/10
I really love that you've used the prefix -claw for a she-cat, first of all. I feel like that isn't done enough. And the name fits her well. I can also sort of see how the cat's colouring would resemble a kestrel. The only issue I have is that it's a little strange to say; it doesn't roll off my tongue as easily as Heroncloud did.
Overall, I think you're doing an excellent job naming your cats, and remember that this is just my opinion, so don't let anything I've said upset you. Have a wonderful day. <3
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Cherrypool: Small tortoiseshell she-cat with white front paws and amber eyes. Caring, gentle, and sweet, often seen as very motherly, but also extremely stubborn.
Fawnberry: Long-legged dusty-brown tabby she-cat with small white paws, a white underbelly, and soft green eyes. Very optimistic and enthusiastic, though she tends to freeze up and panic under pressure.
Rushfrost: Muscular brownish-ginger tabby tom with darker stripes and a white muzzle and chest. A very sweet and helpful cat, but also very shy, and comes across as cold, standoffish, and very focused.
("Rush" refers to the plant.)
Linnetlight: Skinny brown tabby tom with blue eyes. Loud and rash, often rushing into things without using his head at all, but fiercely loyal and driven, very willing to lay his life on the line for good cause as well as stupid.
Fritillarytail: Dark ginger tom with bold, black stripes and a long fluffy tail. Airy and a little unmotivated, but is an excellent hunter, and also very friendly.
(If it helps with his description, he sort of looks like a combination of this and this.)