I don't see why this is even a problem for Clanner Playoffs, Clans today consist of players skilled at different schemes, as an example, I am extremely good at BnG/Roper/Hysteria, pretty good at TTRR/Shopper/WxW, and around average at Elite/T17, other members are strong at schemes others are not, and usually cover all schemes for all clans.
When participating in PO all clans SHOULD have all members on standby as theres 8 legal schemes, so it shouldn't matter what rule there is for who picks what, I honestly feel that the most important thing about PO is who gets 1st pick, and the clan who put in most effort and played the best to win the Season deserves this.