If the radiologists report on the MRI said it was "most likely" an AN, or something to that effect, then you probably don't need another MRI. The diagnosis is usually very clear, and yours sounds like a typical AN to me. They basically consider all ANs to be benign, without even doing any further tests on them. The one or two malignant ones reported in the last twenty years are true exceptions that occurred in very specific and rare circumstances.
I would recommend, whenever possible, that you get copies of the MRI and all reports from your doctors, and carry them with you. I made use of mine on two occasions in particular, one with the insurance company, another with one of the doctors, who had not received copies of all the tests. It can make the process go much smoother, and makes sure that everyone knows all the available information.
Oh and the boys look great, somebody is a proud mom, I would say.