You have equated Jesus' statement, Luke 14:24, "For I tell you (plural), none of those men who were invited shall taste (in the future) of my dinner", with failure to inherit the kingdom and reigning with Christ. With you I agree that they will never inherit the kingdom. But we reign (Greek, basileuo) with Christ by virtue of our adoption as sons (and daughters, of course):
Galatians 4:5, New American Standard Bible (NASB)
5. so that He might redeem those who were under the Law, that we might receive the adoption as sons.
Jesus is king, we are "in Him", part of His family, and are thus royalty:
1 Peter 2:9, New American Standard Bible (NASB)
9. But you are a chosen race, a royal (Greek basileios) priesthood, a holy nation, a people for God’s own possession, so that you may proclaim the excellencies of Him who has called you out of darkness into His marvelous light;
We see that the Greek adjective and verb forms, basileios and basileuo both show that reigning is a prerogative of being part of Christ's royal family. In Christ you reign, out of Christ you do not. Who/what is to be reigned over (angels, new creation?) is not the question. Clearly, there are some who "will never taste my dinner", never be part of the inheritance of the kingdom, never be part of Christ, otherwise, they too would reign. How they would be in Heaven is the challenge for you, or the universalists, to show.
In your post, you have equated a number of concepts that are not necessarily equated in the texts cited. I agree that Christians (those who will reign with Christ) have been "adopted as sons," that we are "invited to the feast," and also that we are "In Christ." This being the case, we may be inclined to consider all of these categories to be equivalent and interchangeable concepts. In fact, however, they may merely be
overlapping, rather than
equivalent, categories.
Of four of my children, it can be said a) that they are my children; b) that they live in the same State that I live in; and c) that I married their mother when I was 28 years old. These statements would all be true, but they are not interchangeable concepts, and while statement "a" would apply to my oldest daughter, the other two would not. There are a large number of things said about Christians, of which some may, and others may not, apply to persons reigned over in the new earth.
Do we know for certain that one must participate in "the feast," or be an "adopted child of God" or "in Christ" (in the Pauline sense of that word) in order to live in the new earth? I don't know if this is so. If you do, you must have information not readily available to me.
How they would be in Heaven is the challenge for you, or the universalists, to show.
I don't expect anyone, after the judgment, to be living in "heaven."