When will the dead be resurrected, and how? Will everyone merit resurrection?
The redemption will follow this sequence: The Holy Temple will be rebuilt, the exiles will be gathered in, and later the dead will be resurrected. Both those who were buried in Israel, as well as those buried outside the land, will be resurrected in Israel. The Angel Gabriel will transport the bodies from outside of Israel into the land. The resurrection will take place in Israel, since G-d swore that He would rebuild Jerusalem to be indestructible. The soul will reenter the body only in a place that will stand forever, so that the soul will likewise live on forever. (All of Israel is considered to be like Jerusalem in this context.)
All of Israel, without exception, will have a share in the World to Come. Even those sinners of whom the sages said they will not have a share in the World to Come, will also be resurrected. However, their original bodies will not return to life. Rather, their Divine souls will return in a different body. Although the unworthy will have no independent and separate share, they will still derive benefit and sustenance from a storehouse of charitable bequests which are hidden away for those who did not merit their own share in the World to Come.
The body will be resurrected in the same condition as it left the world. If someone was ill, or blind, or deaf before passing away, G-d will resurrect him in that manner and then heal him, as the verse states: "Let them arise as they left, and I shall heal them."
(From Exile to Redemption, vol. II, pp. 72-73. Teshuvos U'biurim, Sanhedrin 11:1)