Can I mix different guppies

Yes, you can have two male guppies together. Male guppies have no problem cohabiting. With that said, male guppies can sometimes exhibit aggression towards other males. For example, they may chase each other to assert dominance or fight over a female. (source)
Guppies should be kept in trios – 2 females to each male. Yeah, this is so important we’re sayin’ it twice. Not only does this better the chances of reproduction, but female guppies are also less likely to become territorial than males- so you’re more likely to keep a peaceful aquarium. Sep 30, 2021 (source)
https://www.youtube.com/watch?v=UJNic5gddy0
Guppies and Mollies can easily create hybrids if they are kept in the right conditions. There are two names for two types of hybrids. A hybrid fry from a male Guppy and a female Molly is called Golly, whereas a fry from a male Molly and a female Guppy is called Muppy. (source)
Generally, you should keep guppies in groups. And ideally, you should keep at least a trio of guppies in at least a 5-gallon fish tank. You can keep more than a trio of guppies but then you will also need to increase the tank size of your fish tank according to the number of fish you are going to keep in the tank. Oct 16, 2021 (source)
For a one-gallon tank, a group of three or four is okay, as long as you keep the tank clean and install proper filtration for your tank. It’s good to keep two females for each male Guppy to prevent the males from exhibiting aggressive and territorial behavior. It also makes make mating easier. Oct 26, 2020 (source)
Male guppies mature in 7 weeks or less. Total lifespan of guppies in the wild varies greatly, but it is typically around 2 years. (source)
A 5-gallon aquarium is suitable for a group of 4 or 5 MALE guppies. Guppies are live-bearing fish, meaning the females give birth to live, free-swimming baby fish. (source)
Keep at least 6 male guppies in a tank This is important to spread out the aggression among the fish. If you keep less than six guppies, say you kept only three guppies in a tank then there is a possibility that the two guppies will target only one guppy. This can cause stress to the target fish. May 14, 2021 (source)
Anyway, to cut a long story short, yes, male guppies fight, and yes, if their fins are repeatedly damaged then problems like finrot can occur. They may calm down once a pecking order is established, but don’t bank on it. (source)
One of the most common signs of aggression is when one guppy is constantly chasing another. This is because they’re trying to assert their dominance by scaring them and attacking them. While it occurs more in males, it doesn’t mean females won’t do it either (you’ll find out more about this later). (source)