In an online chat on wandsandworlds.com, Erin Hunter revealed that Runningnose died of a cold between the second and third series.
Runningnose, a character from the Warriors book series, was killed by Darkstripe while attempting to protect Sorreltail's kits from a badger attack. Darkstripe was a treacherous warrior who betrayed his Clanmates and aligned himself with enemy forces.
Spiderleg did not die yet in the series.
There's a lot. Here are the listed ones I know and can remember: Redtail Lionheart Bluestar Willowpelt Whitestorm Sootfur Brindleface Tigerstar Marshkit (Ferncloud kit) Yellowfang Yellowfang's unamed kits Brokenstar Crookedstar Nightstar Cinderfur Tallstar Mudclaw Dappletail Swiftpaw Hawkfrost Goldenflower Patchpelt One-eye Halftail Heavystep Whitethroat Feathertail Silverstream Oakheart Mosskit (Bluestar's kit)
No, her death is not recorded.
So far she has not died, and it is possible she will not die in the series, but retire.
Leopardstar dies in Fading Echoes
Blossomkit is a pure white she-cat who was alive when Brokenstar was leader of ShadowClan, and died when he made her fight much to early. Rock mentions that when she was brought to Runningnose her fur was ripped off, and her pelt was as red as deathberries.
Not so far as the end of the Power of Three.
I'm unable to predict specific events in a book series. In the Warriors series, characters face various challenges and outcomes that are determined by the story's plot. It's best to read the books to find out what happens to Leafpool.
The first series is just the Warriors series. It starts with Into the Wild.
Heavystep, a ThunderClan warrior in the Warriors series, dies twice in different books: once in a battle against ShadowClan in the original series and then again in a battle against the badgers in the later series.
Yes, Foxleap dies in the Warriors series. He dies in the battle against the Dark Forest.