He's now playing in a RMF/RWF role for Universidad Católica. I'd register SMF as his natural position, add WF as a secondary one, and quit CMF because he hasn't played in that position for ages.
First he needs to get a provisional permision before being allowed to play for Alianza. After then, the player and both clubs involved (Alianza and U. Católica) will face each other under the FIFA laws to determine his future. However, I feel Alianza will face a similar fate than Sion (see their thread in UEFA section).