User blog comment:Jkphantom9/Volume 3 Episode 6 Preview/@comment-99.182.122.143-20151210034534

So:

Round One 4-on-4: RWBY VS ABRN JNPR VS BRNZ CNSM (Crimson makes the most sense) VS ???? SSSN VS NDGO Unseen: CRDL VS ???? PNCL (pencil, just to be funny) VS ???? CFVY VS ???? FNKI VS ????

Round Two 2-on-2: Emerald and Mercury of CMSN VS Coco and Yatsuhashi of CFVY Penny and Ciel of PNCL VS Russel and Sky of CRDL Weiss and Yang of RWBY VS Flynt and Katt of FNKI Unseen: Sun and Neptune of SSSN VS JNPR (likely Ren and Pyrrha)

Yang of RWBY VS Mercury of CMSN Unseen: Penny of PNCL VS one from either SSSN or JNPR (likely Sun or Pyrrha)

Another possibility is that Mercury already fought and defeated Penny while Yang defeated Sun or Pyrrha, then we'd be left with the final final of Yang versus Mercury.