I have two new silicone molds that are smaller and more finely detailed than I anticipated.  I had hoped to use candy melts but those are breaking when I try to remove from the mold. I have isomalt but I have not used it before; and I was hoping for a more intensely color decoration. I don't know if it would help to add corn syrup or glucose to the candy melts, or should I just move on to gumpaste or fondant? It is for a children's party so I would prefer it be edible

W/o seeing the mold my guess is you need to use gp/fondant.,

@flowergrower ‍, this sounds like a lace mold - very shallow with fine, delicate lines made of very flexible silicone?  If it is a lace mold, the only thing I know of that will work is cake lace, purchased or homemade.

If they are the fondant type molds and just more detailed than usual, you can use modeling chocolate which is made of  candy melts and corn syrup.   I have done very delicate models using modeling chocolate, filled the mold and placed it in the freezer until the chocolate was hard.  Freezing makes it very easy to remove without damage.