Thanks for updating this site with Becca's story. I haven't been to this site for some time, it's great to see more stories! With the rarity of CMTC it's hard to connect with other parents.
My son was diagnosed with CMTC shortly after birth, he is 3 years old now. It affects his right arm (running from his shoulder to his hand). His right arm and hand are smaller and slightly shorter than the left and have the characteristic "mottled" appearance but he still uses it the same. He is a very healthy, active boy and we know how fortunate he is to not have any of the other possible associated problems that can go along with CMTC.
Just wanted to wish you luck with all your upcoming appointments and I hope you find all the answers you are looking for.