Hi, 1 Cor 10:31.

I believe First Fruits will be fullfilled by Christ returning to gather His
church, Day of Atonement by His Second Coming, and Feast of Tabernacles by
the establishment of His millenial kingdom.  Zola Levitt has a good booklet
on this "The Seven Feasts of Israel".

The conclusion that I found, is that if the tribulation started this year
and ended on Day of Atonement (Oct 3) 2014, mid-trib would fall exactly on
First Fruits (Easter) 2011.  If the AC is mortally wounded on mid-trib, he
will counterfeit his resurrection on the very day of Easter.