From my last two trips, the "campfire" at AKL has been a firepit near Arusha Rock; it is a group of storytellers, who tell stories about the land of Africa, the animals, etc. If there is inclement weather, they move it inside to the fire place in the lobby. Very enchanting.
Over at Kidani Village, there is an area right outside the entrance to Sanaa. We did this the last two years. There is a long walkway out onto the Savannah and there is a fire pit at the end. They have CM's out at night with night vision goggles, so you can see the animals at night. We have always gone right after dusk, so I don't know how long it lasts. Also, when you exit the doors, you can look up and see a grouping of rocking chairs on a second floor balcony that has another viewing area. We had two tired children last year and didn't get a chance to go there.
I would do it with an ADR for dinner, at either place - I love Jiko's and Sanaa is one of my favorite places now.