Cherry would be good for the pork. If you do smoke the lamb, I think that the pecan would give a good flavor. I received some pecan in a trade with BrisketBob in El Paso. I used while grilling steaks and it gave the steaks a nice mellow nutty flavor. Different than oak or hickory.
I would actually cook the lamb on the fire box end. That way you will get some smoke on it and the heat will be higher to seal in the juices faster. This is JMO.
Here is the hard part. You may have to do this 3-4 times before you get what you want.