I don't know why you made several threads asking about keeping fish with a betta, only to ignore all advice and do it anyway...
Why do you think you should have more than three? They're not a schooling fish like tetra. Where did you get that incorrect info from?
With a trio, fry will inevitably happen, if the betta doesn't kill the females before they have fry. Then the fry will likely be eaten by the adult guppies and betta. If they aren't eaten, then the tank will rapidly become overstocked with guppies. Are you okay with that? Or will you want a breeder box/nursery tank to raise the fry?
It's not a good idea to keep guppies with a betta. Not good for either species. Bettas are a SOLITARY and TERRITORIAL fish, and now yours has to share it's territory with three random fish that it can't drive away, and the guppies are sharing space with a predatory fish that is capable of killing them, increasing stress for all of the fish.
So bettas with other fish = not good. Trying to keep a betta with a guppy breeding set up = even worse.