LOL! He can't catch popups or throw, but overall he is adequate in the field. At Bat he has been pretty consistent at getting on base and his power has come in streaks.
You weren't comparing Moncada to Mays, but you were making a comparison with regard to the situation that they both struggled when they came to the major leagues. Even that is not an analogous situation for the reasons that I stated.
And after you use and lose your challenge, you can still ask the umps to review at their discretion. Sometimes they do and sometimes they don't. There doesn't seem to be any rhyme or reason that goes along with the exercise of discretion.