I agree the 3 harvests represent the resurrections. Just about everything in the NT is already laid out in the OT. The natural, physical/literal harvests, point to the spiritual, resurrections
1 Cor 10 These things happened to them as examples and were written for our instruction, on whom the ends of the ages have come.
1 Cor 15: 42So also is the resurrection of the dead. It is sown a perishable body, it is raised an imperishable body; 43it is sown in dishonor, it is raised in glory; it is sown in weakness, it is raised in power; 44it is sown a natural body, it is raised a spiritual body. If there is a natural body, there is also a spiritual body. 45So also it is written, “The first MAN, Adam, BECAME A LIVING SOUL.” The last Adam became a life-giving spirit. 46**However, the spiritual is not first, but the natural; then the spiritual. **47The first man is from the earth, earthy; the second man is from heaven. 48As is the earthy, so also are those who are earthy; and as is the heavenly, so also are those who are heavenly. 49Just as we have borne the image of the earthy, we will also bear the image of the heavenly.
The above passage comes right after this:
1 Cor 15: 22For as in Adam all die, so also in Christ all will be made alive. 23But each in his own order: Christ the first fruits(possibly translate the anointed firstfruits/barley/passover), after that those who are Christ’s at His coming(wheat harvest/pentecost/church), 24then comes the end(grape harvest/tabernacles), when He hands over the kingdom to the God and Father, when He has abolished all rule and all authority and power. 25For He must reign until He has put all His enemies under His feet. 26The last enemy that will be abolished is death. 27For HE HAS PUT ALL THINGS IN SUBJECTION UNDER HIS FEET. But when He says, “All things are put in subjection,” it is evident that He is excepted who put all things in subjection to Him. 28When all things are subjected to Him, then the Son Himself also will be subjected to the One who subjected all things to Him, so that God may be all in all.
Also in REV, it talks about those who dwell in heaven – overcomers/ barley company
those who dwell on the earth – wheat company/most christians
those who dwell in the sea – grape company/ unsaved
does anyone really live in the sea? do the disciples really fish men out of the sea?
This may be the barley harvest, the out-resurrection or exanastasis occurs only here:
Phi 3:11 (Amplified) That if possible I may attain to the [spiritual and moral] resurrection [that lifts me] out from among the dead [even while in the body].
(NRSV)if somehow I may attain the resurrection from the dead.
Heb 3 and 4 speaks of entering into His rest, speaking of the promised land, which is what the Israelites were to do at tabernacles, but they failed to do. But we should strive to enter that rest.