Okay, I was wrong. I was comvinced Tiny Vader was a she. I saw the pink room and the baby doll, and no sister in sight and proclaimed "Tiny Darth Vader is a GIRL!". But alas, I was wrong. Tiny Vader is played by the adorable and talented (how did he emote so much in a full costume?) 6 year old Max.
In this clip from the Today show Vader uses the force before unmasking:
Of note: Like the "real" Darth Vader, Max depends on technology to keep him healthy - he has a pacemaker.