Crystal is not just decently represented, she's very well represented in the population. Every cub born in the population in the last 10 years (besides Luna) is either her cub or grandcub. However, she is much more valuable than her late mate Marty since she was imported from Europe and has no other relatives besides her offspring and grand offspring. Nuka is unrelated to the Aussie x Arki line (which Marty comes from) so his and Crystal's cubs will be much more genetically valuable than Marty and Crystal's progeny.
I'm genuinely surprised Crystal didn't have cubs this past season as she has consistently had cubs every 3 years since 2006 but in the end, it's a good thing she didn't since Nuka x Crystal cubs are now a possibility.
And yeah, it's surprising and unfortunate that Columbus is without a male this season, I and several others were convinced Lee would move back but I guess that's not going to happen.
We need every female breeding since the population is doing so poorly so I'm rather disappointed Aurora, Anana, and the Oregon girls (Amelia Gray and Nora) are all without a mate this season.