yeah, you can adopt they all together, they're friends and go on adventures to save the world or collect some turnips... idk, you can make whatever you want with them :p

You are free to use the characters for personal purposes however you see fit; you can trade or resell them if you wish, and you can also use them commercially in your own works—such as games, comics, or similar projects—without needing to pay me any additional fees (though in that case, I would appreciate being credited in some way as the character designer).