Will fancy guppies (males) work well in this enviroment?

The thing with guppies is that they like warmer temperatures like in the 80s and your other fish may not be able to tolerate that. Guppies are pretty fast swimmers and your other fish may not be able to catch them even if they wanted to as long as you add in some plants and bridges for the guppies to hide in. If you have a warm tank and can add in hiding spots, then give it a go! Just get like 2 or 3 guppies and see what happens.