I'll tell you what I did, and my plan, and we can see if it mirrors any to help you.
I booked a package through a
travel agency, with 10 day park hoppers and deluxe dining. My travel agency mails me my tickets about 30 days prior to me leaving. Once there, I am exchanging my ten day tickets for my AP's. This is not effecting my dining package, which is already paid for with my package. In essence, they've sold me the package, it's up to me if I want to upgrade my tickets or not. Upgrading to the APs won't make my dining go away. I have two other reservations booked after my travel agency package, both booked AP room only + dining.
From everything I've read, you'll be able to take your 10 day tickets and upgrade them to APs once you're there without there being any problems with your existing dining. If on a future trip you want to add dining, you'll use the AP room only + dining thing.
You don't have to upgrade your tickets on day one, you can upgrade them anytime within 14 days of activating them. They will still credit the full 10 day amount to the annual pass, however the start date for your annual pass will be the day that you activated your ticket. Like, if you don't upgrade until day 9 on the ticket, your annual pass backdates to the first day.
Also, you can't combine tickets (like the 10 day and the 1 day) to use as credit towards one pass. You can upgrade either one, in this case upgrading the 10 day makes more sense. You could use your 1 day bases, then activate your ten day tickets, which gives you one more day on your passes in the long run.
If you have the water parks on your 10 day tickets, you'll have to upgrade to premium passes. (from what I've read, I've been investigating this pretty thoroughly but could have missed something.) This MIGHT be only if you've already used one of the days on it or if you've already used one of the water parks on it. If you exchange it before using any days on it, that might not be the case. Allears has a lot of info on this.
By the way, I did check with my travel agency about upgrading once I'm there, and she said I can do that if I want, it's not going to affect the package I've booked already.