Bro Berk Hammond
You are absolutely correct in limiting the special days to the Three Feasts of the Lord.
To further show importance of the three, note that they are all first day feasts.
This in itself should have drawn attention to them.
Unleavended bread begins on the 15th which is a first day of the week. This was fulfilled with the resurrection of the Lord. (THE HEAD)
Pentecost You count seven weeks from the first day of unleavened bread to the day before Pentecost, or 49 days the fiftieth which is theoretically a first day, but is anchored to the first day of unleavened bread. (THE BODY)
Tabernacles, begins on a first day the 15th and ends on a first day the 22nd .
Its possible that the 15th might bring the HEAD AND BODY TOGETHER, in the rapture, followed by a 7year consummation and returning from the canopy of heaven for the wedding feast at the end on the 21-22nd of the feast of tabernacles 2017.
Will it happen on the first days? We will find out soon. For sure the first days will have great meaning during the millennium.
First days point to a different dispensation of a new creation or creature.
Maybe this is why John was in the spirit on the Lord ’s Day, Or the day of the Lord begins on a first day of the week.
Daniel W. Lizarraga