Hi Lal,
“A Sakadagami will not come back to the kama loka once born in the deva loka. But he MAY attain the Anagami stage, and be born in the brahma realm before attaining Nibbana.”
Agreed. A Sakadagami in the deva realm can shift gear in his practice and attain Anāgāmi when he is dwelling in the deva realm.
“In the case of Anagami, he may not need to spend the whole maximum possible lifetime for that realm before attaining Nibbana. He may attain Nibbana shortly after being born there; nothing to prevent that.”
Assuming the Anāgāmi lived throughout his life span in the Pure Abodes. He would have a chance to see 2 or even more successive Sammāsambuddhas?