An expansion at Kamogawa is long overdue and as you say, if they do acquire any more males they probably will have to although I'm not entirely sure whether they do have the space around the current complex.Maybe we would see Kamogawa getting an expansion? Grandvista may have to do it if it means they’ll be able to receive more males.
Port of Nagoya could theoretically receive more whales but I’m unsure if they want to mess with the social structure by having an unknown male mix with Earth + Lynn.
Nagoya could easily accommodate another male if they wish - holding two groupings like they previously did. They'd probably like another breeding female though, alongside Lynn.