Their popularity might be directly tied to Okina's, and they are both the stage 5 boss. But yeah, they aren't the most impactful characters in recent Touhou. 'Guess that's what happens when your role is almost literally to be the extensions of someone else's power.
They're still cute though, so I do hope artists and writers can get some fun from them.
Have that same feeling for most of the cast of the new game.
Larva will likely be kept active with Wriggle, Fairies and company. Nemuno, as long as there are morbid cleaver jokes to go around. Aun is a keeper. By the amount of fan art so far, she's one of the darlings in the bunch. Okina is picking up pace and soon surpassing earlier announced characters similar to how Clownpiece trampled pretty much everyone. Narumi is the new Hina. She'll be around. Diehard fans will keep her alive.... as a waifu.
Satono and Mai. So farking dead. They'll soon find themselves in a long term struggle in who gets to be the bun and filling of the Unpopularity Sandwich in the far end of the poll, along with benben and yatsuhashi.