The hadith of ashra mubashara is a forgery because both Umar and AbuBakr wished they were stools of animals. If they were sure of Jannath then why they wished to be stools of animals?
Statement of Umar:
"I wish I was my family's sheep. They would have fattened me up to the maximum. When they were visited by friends, they would have killed me and roasted part of me, and made qadid (meat cut into strips and dried) from the other part of it, then they would have eaten me, and lastly, they would have relieved me with their bowle evacuation ... I wish I had been all that, rather than a human being."
Minhaj as Sunnah, Ibn Taymiyya, vol 3 p 131
Hilyat al Awliya, Ibn Abi Nuaym, vol 1 p 52 .
A supposed statement of Abu Bakr:
He looked at a bird on a tree, then said, "Well done bird ... You eat the fruits, you stand on the trees and you are not accountable to anybody nor indeed can anybody punish you. I wish I was a tree by the road, and that a camel would come along and eat me. then relieve me with his bowel evacuation ... I wish that I had been all that, rather than a human being." Tarikh, Tabari, p 41
al Riyadh al Nadira, vol 1 p 134
Kanz al Ummal, p 361
Minhaj as Sunnah, Ibn Taymiyya, vol 3 p 120