I notice your Czech Dark Pils has North American malt. I would suggest to try German or European malt. There is a difference and if your going into NHC you need every advantage you can. The malt from Germany does have an edge in flavor compared to North American. I wouldn't use it in a American beer, but in a European beer I definitely would. WLP 800 has a reputation of diacetyl, but it's nothing a rest won't fix. You still have time to brew a test, beers aren't due until early June.
The California Common could be made with Wyeast 1007. It's super clean at 58F and it's a true ale yeast. It's a lot crisper than any of the Chico strains. The only problem with 1007 is that it's stubborn to drop, so long lagering is required.
I'm going to enter as well, and I'm changing up yeast a bit too. I've been making German Pils with 34/70 and it's really good. I used to hate that yeast, but now I love it.
Good luck! I hope you win big.