Reproduction for Sanaes is as it normally is. Of course, they could be the offspring of Kanakos and Suwakos too somehow, but there isn't anything that would prohibit Sanaes reproducing themselves with different yukkuri, and I haven't seen anything that commonly suggests otherwise. The wiki states that Sanaes are only offspring of Kanakos and Suwakos, but a lot of the information there is old, page-filler and personal interpretation.