My original draft of Scar included a big bushy beard, but after some soul-searching it just doesn't make sense to me that sarnothi would have facial hair. I can barely rationalize the hair they have already. ;)
Selkie's issues with cold (and by extension all sarnothi) aren't an intolerance so much as a need to avoid hibernation during winter-level temperatures. It's especially important on the surface to avoid hibernation states, because fluctuating temperatures can pull them in and out of torpor, which isn't all that much fun.
Initially I had Then bantering with the two new sarnothi in the final panels, but got to thinking about the reader comments about Selkie breathing in a wetsuit and a funnier idea came in my head. Thanks, everyone.