Don't 4* shark kisame since it's such a waste when you need to finish off other characters. You should probably finish off kakuzu since he'll have skillbooks in the future and he is used a lot recently in China. Also, if you manage to finish him then you can make a team out the three.

Kakuzu hasn't been very impactful since his release on english servers. He needs a specific team and matchup to make use of his scaling. Kisame isn't either, although more than kakuzu- mainly as frontline and chakra battery for deidara or any chakra-hungry team. When more people will get konan, he definitely will be used more often. Both are support ninjas, so neither of them will have enough impact to become core of the team for now. I support Danzo's opinion- if you have to chose from those 2, get kakuzu first. I wouldn't 4* kisame at all, unless you get lucky x80 by accident to put you really close. You should also rethink if you really need either kakuzu or 4* kisame- isnt there a better use of those resources for you?