Welcome to planDisney Nathaniel!
An after Christmas visit to Walt Disney World sounds like fun! The parks and resort hotels will still be all decorated for the holidays so you can enjoy all the sparkling lights and dazzling decorations.
Please know that the week between Christmas and New Year's Eve is extremely busy, so as soon as you confirm your travel dates, you will want to purchase
Theme Park Tickets for each member of your travel party. This next step is VERY important: Check for
Theme Park Reservation availability for your specific date. I just did a quick check, and it looks like the Magic Kingdom is already unavailable for several days during that week. Do not purchase any Theme Park Tickets until you know you will also be able to secure your Theme Park Reservations as BOTH are needed to enter a theme park.
Now for your other questions....
Disney After Hours is a special ticket event that takes place after the parks close. There are no After Hours events planned during that holiday week, but perhaps you can visit another time when you can partake in this late-night park fun! Regarding your Disney Visa card, check the Chase website for all cardholder benefits.
I really hope you are able to visit Walt Disney World during the holidays, but please be prepared as you may need to alter your plans a bit with your park choice and specific date. After checking the website, feel free to stop back to planDisney if you need additional information or help. Whatever you end up planning, I hope your holiday season is full of magic and pixie dust!
Cathy