Looking for some guidance to upgrade my/wife's J tickets (I fares) which are ORD-LAX-HKG-MLE-HKG-ORD to F. A family member has too many Amex points to burn and has graciously offered them for this redemption. The FM is not a AM member at this time. I have an AM account, but a zero mileage balance. It sounds like the way to potentially achieve this is:

1) Call AM and waitlist the upgrades with my account (would this be allowed with a zero balance currently?)
2) FM establishes AM account and adds me/wife to redemption group
3) If upgrade clears, transfer applicable mileage from Amex to FM's AM account
4) I call AM to use apply the sponsor (FM's) mileage to the upgrade award (would FM have to call and apply from his/her end?)

Any guidance is appreciated. Note, FM is not traveling with us.