I agree that they would probably work better as middle names, or as fuller versions so that they’re more distinct but you can still call them [name_m]Finn[/name_m] and [name_f]Quinn[/name_f]. The short versions alone are gonna be mixed up by others at some point unless you use one as a first and one as a middle.
[name_f][/name_f]I’m not a fan of being too matchy matchy with twins either as they are two individuals who deserve to be recognized. I feel like a lot of people get caught up with the fact that they’re twins and have[name_f][/name_f] to match rather than their unique identities beyond how they were born at the same time.