[quote=@carla6677]
Fine for me, if it is that then I can play both twins by myself
You might find that my characters have distinctive traits to certain house because I made them to be in complete opposite houses 
[@KahleenCuthald]
Also can they be related to cannon characters in a realistic way, if not it doesn't matter.
[/quote]

You can play them both, but will have to do two independent character sheets for them.

It depends. How do you wanna relate them? They cannot be the children of cannon characters, but if you have something in mind, feel free to share your idea.