I am looking for some advise in selecting seats for a trip. I am currently DL Silver Medallion and I have a good choice of seats, my wife doesn't have any status.

My question is for the below flights where might EC seats be and if I do select them now and they are not listed as EC seats and they become EC seats will I be able to stay in those seats? Also do you think DL will let me call in now and get my wife seated next to me??

DL 1755 - 11/21/2012 - ATL->LAX (757)
DL 1299 - 11/21/2012 - LAX->KOA (757)

DL 1298 - 11/27/2012 - KOA->LAX (757)
DL 2154 - 11/28/2012 - LAX->ATL (757)