"Think the best option is to make the sale effective January of the next year"
I think you mean to sell in January. You don't get to make it effective on a date of your choosing, beyond choosing the date you are going to close with the buyer. The date used for the 5/10 year look back is what's on the HUD-1 closing statement you will receive at the closing. Other than you and the buyer agreeing on that date, the date of sale you put on your tax return has to be the date on that closing statement.
