Hi Gail ~
That is indeed a tricky question. They may both get so caught up in the magic that they won't think twice about it especially if you act like that's perfectly normal and kind of do some interpreting for them with you're with the characters. When my boys were 4, they thought nothing of it. Around the age of 5 or 6, they started to pay more attention to it. It is also tricky because the "face characters" like the princesses talk and the "fur characters" like Tigger and Pooh do not during meet and greets. However, some characters do talk in shows and parades like
Dream Along with Mickey and
Fantasmic!. It even makes it trickier now that Mickey talks at his meet and greet location in Town Square Theater but not at his other meet and greet locations.
I used to tell my boys that when characters were in the middle of filming movies or TV shows, they weren't allowed to talk to Guests in the parks because they had to rest their voices so they were only allowed to talk in the shows and parades. If they talked to Guests in the parks all day on top of doing the shows and parades, their voices would be too hoarse to film their movies or TV shows. They were usually happy with that explanation and didn't ask again.
Moms Panelist Beth
answered a similar question with some good ideas as well.
Kids are smart and figure things out at a young age. You may be fine for this trip but one day, you'll have to explain that it is all part of the show. It almost tore me apart to admit to that, but I was very pleasantly surprised to find that my boys still love having their pictures taken with all the characters. I found that just as it is for me, the magic of Disney will always be real in their hearts.
Wishing you minnie magical memories :-) Allison V.