In the "Warriors" series by Erin Hunter, Fireheart, later known as Firestar, is a ThunderClan leader. Cinderpaw becomes Cinderpelt and serves as a medicine cat. They do not have kits together as Cinderpelt follows the medicine cat code and cannot have mates or kits. Their relationship remains platonic and respectful throughout the series.
Fireheart's kits are named Leafpool and Squirrelflight. Sandstorm and Firestar do not have kits together.
Some say Brackenpaw and Cinderpaw. Others, Fireheart and Graystripe. I know for a fact that it is Fireheart (later Firestar) and Graystripe it could be fireheart and cinderpaw
No, she has kits with fireheart.
No, Spottedleaf did not have any kits in the Warriors series.
Yes, he does, as you'll see in the second series.
Cloudtail's siblings are Moonshadow, Nettle, and Marsh, who are his littermates. Additionally, he also has two other siblings, Cherrypaw and Cinderpaw.
Fireheart's sister Princess, offered one of her kits to him so that it could train to become a warrior. Fireheart ended up bringing Cloudkit (Later Cloudtail) into the clan :)
When she dies in Twilight, Sorreltail gives birth to 4 kits and one of the kits name is Cinderkit (after Cinderpelt) so she was reborn to have a better life because she always wanted to be a Warrior.
GRAYstripe fell in the river trying to save those drowning kits with fireheart.
*Spoiler Alert* Cinderpelt dies in Series 2 A New Prophecy in book 5 Twilight at the end during the badger attack. She is killed by a badger while delivering Sorreltail's kits in the ThunderClan lake camp's nursery. She is then reincarnated as one of Sorreltail's kits who later became Cinderheart who is currently alive and a ThunderClan Warrior.
The kits that ShadowClan stole from ThunderClan in "Into the Wild" are Mistykit and Stonekit. They were taken by Clawface and given to Brokenstar in exchange for ShadowClan's loyalty.
They didn't get back together, but they did have kits. There kits are Lionblaze, Jayfeather and Hollyleaf. Crowfeather has a kit with Nightcloud named, Breezepelt.