Given the current situation, I believe that this is Kuroneko's last chance at a necklace. Emerald will be almost guaranteed to be a battle between Azusa and Shana only, unless something preposterous like Shana losing (again). Ruby will probably be Azusa or Shana, whoever didn't win Emerald. And I can't see Hinagiku or Eucliwood NOT taking the Diamond necklace. If Kuroneko can barely beat Mio, I shudder to think how she will fare against Shana, who she hasn't faced yet. That almost guarantees a period where she won't be eligible.
Also, the rest of your post seems to assume that neither
Azusa or Shana will be taking the Sapphire necklace - or are you assuming Kuroneko will win by virtue of it being her last real chance? I don't think a 6-1 record results in an 'almost guarantee' of being outside the Necklace Showdown. This period alone shows that the majority of those with 6-1 above made it - surely this will increase as those '7-0'er's become ineligible?
I'm not assuming
neither Azusa nor Shana will take the Sapphire necklace. My post was entirely to campaign for Kuroneko winning the Sapphire necklace (because she won't get another chance), resulting
in neither Azusa nor Shana taking the Sapphire necklace if Kuroneko does win.
And remember that being 6-1 can have higher SDO than 7-0. In short, it's likely that most of Diamond necklace candidates will be 6-1, probably Hinagiku and Eucliwood included. But it's more than just about wins. It's about how how many votes you get too, which is where Tier 1 and WC has an advantage of Tier 2 and Kuroneko, who is Tier 3.
hinakatbklyn pointed out that Kuroneko has not yet faced Shana and Kanade, where she will lose handily. After Sapphire, Kuroneko will only have 1 last chance at a necklace, and she will have to compete against Hinagiku, Eucliwood, and/or Shana/Azusa, AND she needs to have higher
SDO than the aforementioned since she'll likely get less votes.