Firestar and Sandstorm had their kits sometime between the end of the first series and Firestar's Quest.
In the book Firestar's Quest.
No they have kits named leafkit and squirrlekit then they turn into leafpool and squirrelflight. Firestar's mate is Sandstorm. At the end of Firestar's quest they have 2 kits, Leafpool and Squirrelflight. Firestar take sandstorm as his mate in darkest hour then they have kits after there journey to rebuild skyclan who are leafkit and squirrelkit, wo become leafpool and squirrelflight.
The kits are born between series. The last chapter of Firestars quest has it. It doesn't talk about their birth, but it's the first time leafkit and squirrelkit appear
She has it in Firestar's Quest, A super edition!
It's the epilogue (pg.508-510) of Firestar's quest.
She has her two kits, Squirrelkit and Leafkit, in Firestar's Quest. It is soon after she and Firestar return to Thunderclan that she gives birth.
Sandstorm's kits are Squirrelkit (Squirrelflight), and Leafkit (Leafpool).
In the epilogue of Firestar's Quest is when she has her kits.
No, they would have been mates (probility) and firestar may have been mates with spottedleaf instead of sandstorm. if it werent for firestars loylalty sandstorm would have been dustpelts mate.
No, she has kits with fireheart.
Their is no specified time. He would of probably been there at the birth.
No one has sandstorm and Firestar are still alive and they have grand kits