Not really. That's just Nintendo's way of akwonleging that Wario and Waluigi aren't related. If they were, it would've made more sense to call them the "Wario Bros." They're called the "Wicket Bros." because they're always up to no good.
Just think about it, Waluigi has never appeared in any of Wario's stand-alone games while Luigi is almost always the #2 to his brother Mario. If Wario and Waluigi were indeed related, I'm sure Nintendo would've at least given Waluigi his own role in Wario's games but since Waluigi has yet to appear in one and only appears with Wario in the side games, it's safe to say that no, they're not related.