As a filmmaker myself I seriously doubt they'll do it over 90 minutes long. There are a few "rules" (of course in cinema you're always granted a lot of leeway due to the creative aspectects of the art form), that due to a child's span of attention, and TLBT's target audicien cartoon/child movies are usually never longer than 90 minutes, 60 to 70 minutes long is usually what you're looking for.
However, there are exceptions, in comedy you should never exceed 90 minutes either because it's very hard to keep the audience interested in ordinary comedy for longer, however there are a lot of movies that were successful in passing this mark, let's see what LBT XIV has to offer.
I don't mind having kids in cartoon movies with adult voice actors, we often use women to voice young boys, as they do in anime (Son Goku is voiced by a woman), as long as they're professional they can really do a great job. Look at the Simpsons, over 25 years and the voices are pretty much the same.
