As I understand it, the new option to bring in guests for cash/miles is, for Elite+ members, in addition to the existing (2?) free guest allowance. I saw it somewhere (either on the AF/KL website, or possibly in an in-flight magazine - I'll have a look round and report back). So, assuming I'm correct, you and Mrs Cuparte can, between you, guest in either one set of parents (if it's 1 guest per Elite) or both sets of parents (if it's 2 guests allowed).

-- Henry

PS: Are you suggesting, BTW, that your mother(-in-law) isn't worth 35 euros?