The 2 larger fish appear to be a Molly variety but I can't identify exactly what type. Both appear to have gonopodiums so they would be males so no worries about them having any babies.
The other fish could be anything from a Guppy to an Endler to a Gambusia. Since they are wild from a pond, my guess would be Gambusia but since you mentioned the pond having such a large variety of fish in it, it's a guess at best. Once people start mixing the 3 different varieties, they could all be "mutts" or hybrids.
Hope this helps.