Roughing in piping for a drain,sink, and toilet. Can I use an AAV for all of these and place the AAV under the sink. All of the devices are within 12feet of each other and the sink will be located in the middle and the drain pipe is located all in a straight line.

If AAVS are allowed in your area, then I see no reason not to use one as you suggested. For the AAV to be effective, you want to pipe this up so the shower (or tub) drain comes off the toilet drain... the sink drain would be piped off the shower drain. Make sense?

Mark