I too have looked for rapture on a day when the buds on trees are fully formed,
about to break through, but the ground is still cold and only starting to thaw.
I think it's earlier than the May you consider as a likely time. I think it's when
late winter gives way to early spring. I have wondered about this as a possible
time because my online friend Searl had a dream over twenty-five years ago
of the rapture occurring at this season in Ohio; Searl had not considered the rapture
real until he had this dream.
I think your time line of the Seals sounds right except for Seal Five, where you
say those "asleep" in Christ awaken, with the resurrection and rapture occurring
with Seal Six. I think those in Heaven are already awake before the Seals, for
the Apostle Paul says "To be absent from the body is to be with the Lord." It
would not be "with" Him unless one were awake to it.