No problem. That's how we always did it before DS decided he was done with the princesses . We'd arrive 10-15 minutes early to the first one and then hit the second one with plenty of time to spare.
Agree with others, show up 10 mins early for first one so you can be close to the beginning of the line, even if your aren't some of the first in, you should have no problem . The princess meets are in the atrium and the Frozen meets are usually in Animator's Palate, so they aren't that far away from one another.
I asked DCL that question when concierge booked us with those events back to back. The rep stated they were told 30 min separation is enough time to hit both so they do it routinely. I decided to roll the Frozen m&g to later in the day so I didn't have to worry about it.
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