Is it posted which characters are in the meet and greet before actually entering the queue?
Here’s some good and fun info at WDW News Today on that meet and greet. I think the standard is Mickey and Goofy, but I’ve heard that sometimes Pluto or Minnie alternate for Goofy.
Not sure about WDW, but at DLR it remains a mystery until you go back.
During our family visit in late January 2018 the characters at the Chase M&G at EPCOT were Minnie and Pluto. Kylo Ren was at Hollywood Studios. Took about 10 minutes at EPCOT and about 15 at Hollywood Studios.
It’s not posted, but you can kind of peek in or ask the CM or people exiting. We had Pluto and Minnie.