Hmmm, this is a tough call. Assuming you are going during Daylight Savings (if not, it will likely be earlier), the fire lighting begins at 7:30 pm, the singalong at 8:00 pm, and the movie at 8:40.
So, I always plan on at least an hour for dining (keeping in mind that you may not be seated right away). With that in mind, Tusker House is near the back part of the Animal Kingdom, so you have a longer walk to get to the bus stop then wait for the bus and then the ride to Ft. Wilderness. I think it will be tough to make the 7:30 campfire, but the singalong and movie are more likely.
So, if you are unable to make you reservation earlier and would rather try something to make getting to campfire easier (especially since your daughter is a fan of the chipmunks), how about the
Trail's End Restaurant at Ft. Wilderness, which I really think is a hidden secret at WDW. Similarly,
Whispering Canyon Cafe at the Wilderness Lodge is a hoot, not to mention it has boat transportation to Ft. Wilderness.
I hope this helps with your decision making!