I'm pretty sure this is what Terry was talking about (see image). You are best to simply stub the sanitary tee straight out for the sink on the right.
Got it. Trying to do this as simply as possible. Is there any down side to just elbow out the current lav drain to go in the middle of where the double vanity would be and the run a split after the p-trap 2ft each side?
Also, since the supply lines go out on both sides of the wall and essentially crosses the drain pipe, how would I tee out the supplies to the extra sink?