Thanks for the replies. I originally got the ticket line, but she had to transfer me to resort reservations because it is a package reservation, not just tickets. She said she could sell me the holiday party tickets, but not make adjustments to packages.
So she transferred me to a regular CRO CM. She originally quoted me a price based on my original price. When I told her I had the price adjustment in Feb after he construction was announced, she found an "alert" on the reservation. That's when she contacted guest services. I did not speak to guest services myself. But she explained that because I had this "special offer" attached to my reservation, I could not make any changes at all. Not even to increase tickets. Any change at all would remove the special offer. So this is coming from guest services already.
I also received the email about the gift card. I have no idea if we are actually going to get the gift card or not, since we already have the $75 off.
I thought more about it & we also have 1 fastpass that was given at he same time as we got the discount applied. Just 1, not 1 day's worth. So that will help in another day. Luckily my DS & DDIL mostly care about MK & Star Wars stuff. They have no interest in Pandora or FEA at Epcot. They only want AK for the safari. So I can fp one day at DS, 1 at Epcot, MK afternoon with our party tickets & then the safari with the single fp. Then we can add stuff that's available after we increase our tickets. It's just aggravating to have to play this game!
She is a big Harry Potter fan, so we are doing Universal 1 day. I'll have to talk with them later, maybe they'll want 2 days there instead, since we can't increase our tickets now anyway.
Edit to add: the CM did say I can buy & link the holiday tickets. That they are not part of the resort reservation. I hope so, since I'll need to link them in
MDE to make the fastpasses.