No. Your tank is already grotesquely overstocked. You are going to have many deaths as things grow out and those guppies multiply. Dwarves are sensitive, too, and it would just die from the bad water quality.
It is a mistake to insist on cramming a tank with many fish. It is much more enjoyable to have a tank with a few fish of an appropriate size for your tank so they will be healthy. With your current stock there is no way you'll be able to keep good water quality. If you insist on keeping it that way, do not be surprised when an illness wipes out half of your little pets. I know some people consider it "normal" for fish to die, but that is just wrong. It happens because they have been given poor care. I would encourage you to make sure you are giving your fish the best care you can. If you do, you can take pride in having a few fat, happy, fully grown beautiful fish, rather than a tank stuffed with small, unhealthy fish that you constantly have to replace. In your case, in order to accomplish this you are going to have to return about half of them to the petstore, including the BN plec (which is too large for that sized tank as they are heavy waste producers) and the hillstream loach (which should really be in a coldwater tank). I know there is more than one shape available for 15gallons. Do you have a 15 long or a 15 high? If it is a high, I would suggest rehoming the corys, as well. That amount of floor space is too cramped for them. If it is a long, you would be able to get away with keeping them if you rehomed either the guppies or the tetras.