Rockshade, Bouncefire, and Tinycloud
Bouncepaw, it is mentioned in Firestar's Quest.
Poppyfrost's kits are named Cherrykit, Elderkit, and Larchkit.
Mapleshade's kits are named Larchkit, Patchkit, and Petalkit.
Go to parentingweekly.com.
Vixenkit and Grasskit
Snowbird's kits are named Larkpaw, Honeykit, and Leafkit.
Yes, she has kits with Berrynose at the end of The Fourth Apprentice. Their names are unknown right now.
Millie’s kits warrior names are Bumblestrip, Blossomfall, and Briarlight
Sparrowkit, Dewkit, and Mistkit.
Millie's kits are named Brierlight, Flamepaw, Birchfall, and Blossomfall.
They do not have any kits as far as we know, it was never said in the books. But there are a lot of different fan-fics for them and their kits.
Yes, I have read the first 50 pages of The fourth apprentice. Poppyfrost is expecting Berrynose's kits. Edit; The kits names are Molekit and Cherrykit.