Verin mentions it, yes. And Elaida I already explained. Cadsuane says she had eyes and ears on Siuan and Moiraine, but makes no mention of thinking they were working together. Separately, she talks about the trouble Siuan got into by meddling with Rand, but she does so when Siuan's involvement with Rand was common knowledge.

And Saerin mentions Siuan as being one of Elaida's "favorites", but makes no mention of Moiraine or their friendship.

You seem to take any mention of Moiraine or Siuan as a mention of their friendship. Related to Galina, all I could find were Sarene mentioning Moiraine being her friend, in response to Galina claiming Moiriane had faked her death. Separately, Galina mentions leading the circle that stilled Siuan. Nowhere is Moiraine's friendship with Siuan mentioned.

As an example of someone in the loop who didn't know Siuan and Moiraine were plotting, look at Alanna. By tSR, she knows it was Moiraine who found Rand and the others. Yet, in LoC, she's surprised when Verin reveals that Siuan was also part of the effort to find Rand.

Only two people were aware that Moiraine and Siuan were still conspiring together. One was Verin, who always knew it. The other was Elaida, who only began to suspect it after Siuan sent Elayne to Tear.