Yep. That seems like the best approach in terms of schedule, perhaps leaving the attitude thruster system completely intact just because it's already adequate (I think) and thus would save lots of mounting and software changes. However, if the thruster exhaust is going to impinge on the tanks then maybe they'd repeat Grumman's idea of mounting the attitude thrusters on struts. If the schedule isn't critical then further optimizing is probably a good idea (visibility, entry/exit, internal tankage, small breakfast nook, etc).
On the flip side, leaving the thermal protection and parachutes in place would give you a lifeboat useable all the way to splashdown, and if you did just add extras to an existing Dragon you could probably execute the mission with one craft, but with severe performance penalties because your Earth Orbit Insertion fuel would also have to ride all the way down to the moon and back up, unless left in lunar orbit, in which case you've not saved any lunar rendevous requirements.
Given the Falcon9H payloads, you're not going to execute the mission in one launch, so you might as well use most of the Apollo mission profile with multiple launches and LEO rendevous.