Is it permissible for the people of Paradise to exchange gifts among themselves, especially if the first one brought his sapling from "Subhan Allah Al-Azim" and wishes to gift it to someone of a lower rank than him?

The believer must believe in what is stated in the Quran and Sunnah about the people of Paradise and unseen matters, and strive to attain them. If he enters Paradise, Allah will fulfill everything he wishes for, even if it is a gift for his brother, as Allah Almighty says: "For them therein is whatever they desire, [abiding eternally]; it is ever upon your Lord a promise [bindingly] sought." (25:16) and "And for you therein is whatever your souls desire, and for you therein is whatever you request." (41:31). The people of Paradise will not be deprived of anything they wish for, and there is no prohibition against exchanging gifts among them, although the standards of the Hereafter differ from those of this world. Despite the varying ranks of the people of Paradise, each group among them will be content with the blessings Allah has bestowed upon them.