ERICKSON - Were Jesus and Heavenly Father there in pre-existence? if yes, that means they are not in Celestial Kingdom?

JOEL - First of all, our Celestial Kingdom doesn't even exist yet. In the scriptures we are told about the future of this earth:

"Therefore, it must needs be sanctified from all unrighteousness, that it may be prepared for the celestial glory; For after it hath filled the measure of its creation, it shall be crowned with glory, even with the presence of God the Father;
That bodies who are of the celestial kingdom may possess it forever and ever; for, for this intent was it made and created, and for this intent are they sanctified."(Read D&C 88:18-26)

The earth is passing through four stages or degrees:
1. The creation and the condition before the fall of Adam.
2. The telestial condition which has prevailed since the fall of Adam.
3. The terrestrial condition that will prevail when the Savior comes and ushers in the millennial era.
4. The celestial or final state of the earth when it has obtained its exaltation.

Our tenth article of faith tells us that "that the earth will be renewed and receive its paradisiacal glory", the condition that it will be in during the Millenial reign of Jesus.
After that it will be transformed into the Celestial kingdom where the exalted children of God will dwell in His presence. (D&C 88:18-20)

Joseph Smith said that when this earth is redeemed, it "will be rolled back into the presence of God and crowned with celestial glory." (Joseph Smith Papers 1839-1841)

"This earth, in its sanctified and immortal state, will be made like unto crystal and will be a Urim and Thummim to the inhabitants who dwell thereon, whereby all things pertaining to an inferior kingdom, or all kingdoms of a lower order, will be manifest to those who dwell on it; and this earth will be Christ’s." (D&C 130: 9)

So God the Father and Jesus were indeed present with us in the premortal existance, but that was not the Celestial Kingdom that we may some day inherit. We could perhaps say that our premortal life existed in God the Father's own Celestial kingdom, which we have been told is near a great star called Kolob. (Abraham 3: 3-9, See also D&C 130: 6-8)

In the Book of Abraham we are told:
"Kolob, signifying the first creation, nearest to the celestial, or the residence of God." (Book of Abraham, Facsimile 2, Explanations to Fig. 1)