They must have recycled Wayne Allwine's performance as that actor is dead. He died in 2009. He voiced Mickey for 32 years with one of the first performances as Mickey from Mickey's Christmas Carol in 1983. The person who voices him now is Bret Iwan so I'm wondering if there wasn't a typo somewhere.
Also I saw some people missing Christopher Lee but one reason he's not there is because he's 91 years old and doesn't act or voice that much anymore outside of doing tiny roles in various Tim Burton Movies. The last Tim Burton movie he was in was Dark Shadows. I think the last time I heard him voice anything was in 2010 and he voiced the Jabberwocky in Tim Burton's Alice and Wonderland which again is a Tim Burton film
What's kinda funny is that he has recently released a new heavy metal album in May, lol. He's freaking 91 years old and is singing metal.. He could easily come back to voice as Ansem the Wise if he would like to.