Hey there, I registered just so I could reply to to this! I called Verizon twice and it was confirmed that the trade in applies by both CS reps. it sounds like it's recommended to get the trade in process started before you purchase the new phone.
Anyway, canceled my preorder and picked up my RG 128G 7+ at the Apple Store. The purchase at Apple is showing as a completed order on Verizon now and my trade in is showing as eligible for up to $650. I'm mailing it off today.
By the way, no, Apple installments are not the same. You need to set up the monthly carrier device financing when you make the purchase at Apple. The payments are then on your monthly bill from your carrier.