Hiya, Joy!
One reason you may have conflicting opinions is because it's hard to pin down which park to go to which day! A lot of factors go into picking the best day at each park, including major holidays. Your dates fall at the end of the Christmas season, so it's different than recommending days another time of the year.
I tell people to try to avoid the park that has
Extra Magic Hours in the evening. It may be the better park to go to in the morning, but as the day goes by, you'll find that guests gravitate toward the park that will be open later, making that park a bit more crowded.
I like to avoid the
Magic Kingdom on the weekend, if I can. Many guests arrive over the weekend, and many guests also choose to start their vacation with this park. Because the park is smaller, it can feel more crowded on the weekend with the influx of guests beginning their vacation. On the weekends, I recommend either
Epcot or
Disney's Animal Kingdom. Those parks are larger, so even on a more crowded weekend day, you won't feel as tightly packed in, since there's a lot of space to spread out.
Disney's Hollywood Studios is also on the smaller side. I definitely say skip this one on the weekends or on a day the park has extra magic hours. With the new
Toy Story Land, it'll feel crowded.
Have a wonderful time, Joy!
Anna