Yes, you can mount either of the film backs on the AFi body. The way it works is there is a small frame that has the 4 pins on one side and this fits into the camera body as the digital back would. Then the film back latches into the frame. With the 645 film back, you can use the slide to cover the film and pop out the film back rotate it and pop it right back in to change the orientation. Takes like 3 seconds. With the 6060 this is obviously not needed but you could have for example two different types of film each in their own back and you could change back and forth easily.
Recently I bought the AFi back to Maymiya RZ adapter to play with (and only play as the AFi is a much nicer camera) but haven't used it yet but certainly it can be done. There is also an AFi back to 4x5 camera adapter as well.
