I have always found the female guppies hate the breeding traps and get stressed in them. All the fish you have, including the guppies, will eat fry. A well planted tank is best (especially if you can't separate the guppies) with lots of Java moss and water sprite. Plants with lots of bushy, fine leaves. The fry can hide in it and the bigger fish can't reach them.
Guppies reproduce very easily with no special help required. That is why they are also known as the millions fish
If you really want babies then I would separate the guppies from the rest of the fish. You need a sex ratio of 1 male to every 3 or 4 females at least, they are not meant to be kept in pairs. Too many males and the females will be harassed to death.
By the way, the danios and barbs are shoaling fish and happier in groups of 6 or more. Keep an eye on those mussels too. They pollute a tank very quickly if the die.