Okay, well, so far, the Rosy barbs are doing GREAT with the goldfish, and I have found that if I drop the goldfish food first, and then the meatier food, they each eat what they are supposed to, lol. (I make all my own fish food, I have one that is mostly veggie based and one that is mostly meat based.)
I had some Rosy Red minnows in the big tank, and I was worried at first that the big goldfish would eat them (1 foot goldy versus 2 inch minnow....) That did NOT happen, but I ended up removing the minnows after a week or so. They were picking horribly at the goldies, biting at their fins and slimecoats. They are now in a tank with similarly sized fish, and everyone is happy.
Conclusion - Rosy barbs, yes, Rosy minnows, no.
Kristina