I'd venture that Maxima would have used her base in New York and job in the financial industry to land the Euro/Anglo husband-with-the-deep pockets she seems to have been angling for, according to New York rumors (this may well be malicious gossip, but let's face it, does Maxima strike any of you as the type to get hitched to the cute-but-broke plummer down the street? Didn't think so either.)
Letizia would have stayed where she was: a news anchor of ever increasing stardom. She would have gone on, probably, to marry an equally accomplished husband, had her current one not existed, let's say.
Mary would have dated and eventually married a hunky Aussie who'd be working in the advertising/marketing biz. She, meanwhile, would stick around in the property development business, in some sort of marketing capacity.
Mette Marit would have, by now, have a few more kids with a handsome Norwegian who's maybe in the oil business (Better than hunting wales, non?), maybe someone she met through Eva Sannum (what on the planet happened to that one?!)
hah, this is fun, people!