GW, I have been told that MC is not helpful if there is an active A, whether EA or PA. Most of the time WAS will use MC to their advantage... "See, we tried MC and it didn't work, therefore I am justified." Or, they are just not honest in MC so it really doesn't help. If she is willing to provide total transparency and tell you she is commiting to making the M work, then MC would be helpful. Personally, I would prefer a professional to a pastor, only because I don't know that all pastors have been trained properly... and there are pretty high stakes here!
About the cell phone issue, I don't think you should confront. However, snooping is another issue, and there seem to be people who have been able to move the DBing forward by getting proof and THEN confronting.
Puppy is the expert on that... If you see him posting on another thread you can ask him to stop by yours and take a look.
About contact while she is away, that is tricky from my POV. That was my H's complaint as well prior to his A (that I was not taking enough iniative with contact/communication etc.) So I battled this question often. My conclusion on this is that when the WAS is in the fog (which your W seems to be) it doesn't matter if you are the PERFECT S and do everything they ever wanted you to do, they remain in the fog until that A gets busted somehow or ends completely... NC. So, you certainly can contact her, but it may not be received the way you would like it to be. I think you should contact her because it is the right thing to do... you are her H. But, not because you are hoping to get some kind of reaction out of her. That is one of the primary DB philosophies... do what is right for your kids, for you and even for your M, but not to get a reaction or response, but simply because it is right. So, yes contact her, but keep your expectations low, don't go overboard, don't pursue, keep it minimal... the kids want to say hi etc. That's my POV, but I'm sure there are others who would say don't contact at all... let her do the work.
BTW... good job on not rescuing her by doing stuff for her this morning!