No one could be resurrected or glorified from all the other creations until the Savior was resurrected and glorified. During that long wait, what did glorified bodies do that were eligible for celestial glory? No one can go to a celestial home until each has been glorified.
As you have suggested, all righteous dead waited in the Spirit World for Christ’s resurrection to be accomplished.
Spirits, when they leave their bodies, do not dwell with the Father and the Son, but live in the Spirit world, where there are places prepared for them. . . No man can enter the celestial kingdom and be crowned with a celestial glory, until he gets his resurrected body. (Teachings of Brigham Young)
Additionally, many righteous dead may be called to wait for resurrection until after the Second Coming. However, although they dwell in the Spirit World, it does not mean there was not work for them to do. Doctrine & Covenants 129 provides additional understanding on this:
There are two kinds of beings in heaven, namely: Angels, who are resurrected personages, having bodies of flesh and bones . . . Secondly: the spirits of just men made perfect, they who are not resurrected, but inherit the same glory. . . If he be the spirit of a just man made perfect he will come in his glory; for that is the only way he can appear . . . but he will still deliver his message.
From this passage we can see that, although one may have to wait to be resurrected, righteous spirits worthy of Celestial glory may still be tasked as ministering spirits of God. God has a work for each of us and will use us where and how needed. The state of our physical bodies will not impede us from doing the Lord’s work, nor will it impede Him from using us as needed.
Doubtless, this same work is being accomplished by our Father and our Savior all over the universe, as expressed by Elder Bruce R. McConkie:
Just as the creative and redemptive powers of Christ extend to the earth and all things thereon, as also to the infinite expanse of worlds in immensity, so the power of the resurrection is universal in scope. Man, the earth, and all life thereon will come forth in the resurrection. And the resurrection applies to and is going on in other worlds and other galaxies. – As quoted – Ensign – April 1976
That said, we would do well to remember the Lord’s words to Moses regarding other worlds:
And worlds without number have I created; . . . But only an account of this earth, and the inhabitants thereof, give I unto you. . .
As a general rule, it is wise to keep speculation to a minimum. However, I am confident that in His wisdom and perfection, the Lord will always act in the most efficient and beneficial way to advance both His plan as well as each of His children. I am grateful for the Lord’s plan, and the truths he has revealed, and am excited for those we will be blessed to learn throughout our lives, and in the hereafter.