Romans 11:25-32

[Amanah]

I have questions about Roman's 11:25-32

25 For I would not, brethren, that ye should be ignorant of this mystery, lest ye should be wise in your own conceits; that blindness in part is happened to Israel, until the fulness of the Gentiles be come in.
26 And so all Israel shall be saved: as it is written, There shall come out of Sion the Deliverer, and shall turn away ungodliness from Jacob:
27 For this is my covenant unto them, when I shall take away their sins.
28 As concerning the gospel, they are enemies for your sakes: but as touching the election, they are beloved for the father's sakes.
29 For the gifts and calling of God are without repentance.
30 For as ye in times past have not believed God, yet have now obtained mercy through their unbelief:
31 Even so have these also now not believed, that through your mercy they also may obtain mercy.
32 For God hath concluded them all in unbelief, that he might have mercy upon all.

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What is meant by the fullness of the gentiles?

Isnt This passage referring to the biological ancestors of Abraham being grafted back into the root?

In reading pre Dispensational commentary by authors such as John Gill, Eldon Ladd, and others, there seems to an expectation of a revival among the ancestors of Abraham?

I also see in verse 32, that the ultimate end goal is that God will have mercy on all. Yet there seems to be a time after the gentile revival when there will be a Jewish revival?