Jeff was way too easy to hit to have a chance against Olivares. Ruben stops him both times, just later at Feather.
Fenech was very raw IMO at 118, getting by on basically sheer physicality. Olivares plays matador and walks him onto endless left hooks. I'd say Fenech goes the distance with basically anyone below FW, but maybe Olivares could stop him. If anyone could, it's Ruben or Zarate. At 126, Ruben gets his ass kicked. He'd give a good account of himself while landing with the left hook, like Callejas did, but Fenech catches up to him some time after ten and stops Olivares. It'd be a messy TKO after being wore down for rounds on end. It'd be a fight which could shorten a prime.