To be perfectly fair, I remember a discussion in Batoto about the cat's name.
The best translation of konbu is "kelp", the word for that specific kind of brown alga. Seaweed is a more generic word and the word for it in JP is nori. I seem to recall an Helvetica member saying the discussion is much ado about nothing, and I concur, but there used to be a different scanlator in Tumblr who used Kelp for the cat and though their overall quality was inferior to Helvetica's, I think they got that one right.
Kelp sounds a little less lame than Seaweed, in my opinion.