i'd thought though that having two age groups, (little children and young adults) wouldnt mix too well. if i was a little 7 year old girl and my mommy took me to an MLP convention i'd be pretty scared by all the big strangers running around dressed up as rainbow dash
it'd probably be the same as taking them to a circus or amusement parks with clowns and such. little kids will enjoy it if it has things they like.
it might be awkward for some (I know it would be for me, but that's my personality type), but others probably don't care
Hasbro doesn't run the convention, so it's not affecting them.