I mixed Gold and SIlver Saums before and the Fry just come out mixed....alot more Silver Saums than Golds tho..out numbered by ten to 1.
IMO Silver Saums and Gold Saums are the same fish.. i mean theres no evidence to claim either way, they are indentical in every single way other than the colour of the tips of there fins.... i mean in my community tank i have Neon Tetras that have slight green tint to them...don't mean they are not Neon Tetras
As for Rivulatus..i have never seen one in real life, just pics and they always look like a dull Silver Saum to me, so i expect you would get the same results if you mixed them with a gold.