I'm going to be serious for a moment here — I'm really not seeing the shutdowns that tictoc nerd and rouward are seeing in the second season of the anime. I'd actually suggest that the way that Kasumi proudly wore her hairpin at a critical moment and was super comfortable volunteering Shizuku's house for the "training camp" both serve to reinforce their relationship. (And the way that Ophelia was hanging out with Kasumi while she was "plotting" at night suggests she's over there a lot.) As for KasuPomu, I'd point to the bit in the stills where Ayumu is helping Kasumi with her tie, Kasumi is blushing, and half the cast is peeking around the corner like they're watching something naughty. (I'd also say that A•Zu•Na was presented more as Shizuku shipping SetsuPomu than a thruple.)
Now, I would say the second season felt something of a reaction to the way the first season really did feel like it was trying to push particular couples — or rather, the way that certain characters weren't explored outside of being in a pairing; EmmaKarin is probably the most pointed example. The mandate to establish the subunits is probably a big part of that — you must have Ai and Karin actually talking with each other to make DiverDiva make any sense at all — but there definitely was an effort, even beyond that, to mix the established groups up a bit. That said, there was still some reinforcement of those first-season pairs: the ShizuKasu stuff I mentioned, or Rina hugging Ai before the DiverDiva live, or Karin still leaning on Emma a lot, or all the YuPomu reinforcement.
(If you want official KasuPomu, I'd actually say that that's strongest in Nijiyon, and in the occasional game remarks about how much Kasumi considers her her strongest rival.)