We have a 4.5 yr old daughter who fits some of the description of cdls (After reading on your post i done some research), problem is she has not been diagnosed til today. & we did not pursue it either but focus purely on her needs. However it was glaring from her birth of her physical defect; namely microcephaly.
During the confusion initial year we had her go through an MRI, it was inconclusive on the doctor's point of view and all he could do was murmur a 'i guess it will be a 5% chance it will happen in your next child' which was not good enough for us, and til today the MRI hardcopies are sitting in a corner of the drawer collecting dust.
I think the purpose of these scans are to find out the diagnosis and since in your situation you already have a diagnosis we think it is not necessary to go through scans etc
For us we had an initial EEG done as well to determine daughter's sleeping issues. & we did find out that because of her microcephaly, she had very bad spiking brain activity during deep sleep, thats why she was always screaming in the middle of her sleep.
best of luck