Yes I would defineately do Sea World first , the WDW parks will really empty out after the 1st and will be much more enjoyable...Sea World too is a good park and you will like it, I hadn't been in about 10 years and went last year I was really impressed in how AH had spent the money to fix it up. But if you do want to do a WDW park before then I would try either MGM or AK. Then concentrate on EPCOT and the MK after the 1st. Remember to bring some warm clothes since Jan weather can sometimes be iffy especially in the evenings. Also if you have time check out some of the resorts for all their great holiday decorations!