You are an artist! And ambitious, I admire the "sculpture" very much. Well done. I've only worked with sphagnum moss one time and it died by the time summer ended. I kept it watered, too but it kind of dried up. This was topiary I made for outdoors with a chicken wire frame.

Oh, I took another look at the photos and I see the fig is planted in a pot at the foot of the topiary frame not actually in the moss. Will the topiary be kept indoors? I've never grown creeping fig but if it's like an ivy I should think it will cover the frame eventually and then the moss won't be needed anyway if it's rooted in the pot below.

Now, what is the purpose of the pot in her chest? Is it to be planted with another plant later? If so, that's a unique idea.

As far as maintenance, I'd have to look up creeping fig and see if it likes constant trimming of its foliage.