Hi and welcome to FishLore!
Goldfish and guppies need totally different environments.
Guppies need warm water - around 76-78F
Goldfish are cool water fish and need around 65-72F. since they are such big waste proucers they need 20G for the first fish and 10g for each additional fish .. they will not reach their natural potential size in smaller tanks either.
Most fish will eat anything big enough to fit in its mouth. One of these days the goldfish will be big enough to eat the guppies and will definately eat teh fry. Hope that helps

Carol