Their are no cases of this happening in the series, but yes, this is possible.
If the leader dies in the warrior book series, the deputy would take over. Like, when Bluestar dies--Fireheart was the deputy--Fireheart would take over the leadership of the Clan.
In the Warriors book series it is second in command of the Leader. It organizes Patrols and takes charge while the leader is gone.
In the Warriors series, there are various ranks and positions within the clans, including leader, deputy, medicine cat, warriors, apprentices, queens, elders, and kits. Each position plays a vital role in maintaining the clan's balance, traditions, and way of life.
The first deputy of ThunderClan in the Warriors book series was Bluefur, who was later known as Bluestar when she became the leader of the clan.
Not during the current series--right now, in the books, Firestar is leader, and Brambleclaw is deputy, meaning Brambleclaw will be Firestar's successor. But, when Brambleclaw becomes leader there is a chance Brackenfur (Brackenpaw) could become leader.
Tawnypelt's mate in the Warriors series is Rowanclaw, a former ShadowClan deputy who later becomes ShadowClan's leader. They have kits together named Tigerstar, Dawnpelt, and Flametail.
In the Warriors book series, if a leader dies, the next in line is typically the deputy, who would then become the new leader. The deputy is chosen by the leader themselves and usually has shown leadership qualities.
No. Pineclaw was around long before Pinestar, and it is unknown what Pinestar's warrior name was.
Successors in the Warriors series are often referred to as apprentices. These are young cats who are being trained to become warriors by their mentors, learning the skills and traditions of their Clan.
A deputy substitute is a person who temporarily takes on the responsibilities and duties of a deputy when the deputy is absent or unable to perform their duties. They step in to ensure the smooth continuation of operations in the absence of the regular deputy.
Blue Star is a former leader of ThunderClan, making her a significant and respected figure in the "Warriors" series. She served as ThunderClan's leader before Firestar, guiding the clan through many challenges and battles with wisdom and strength.
Brambleclaw became deputy in the book "Moonrise" in the Warriors series by Erin Hunter.