I could definitely see Oscar Lindberg as a serviceable 4C, which would allow Cizikas to play 3C and then they have Komarov as the emergency center in case of an injury during a game. I would be fine with bringing in Lindberg on a PTO or reasonable one-year deal.
Honestly, if we are talking about a good fit one a one-year deal, I really believe that Vladislav Namestnikov would be a solid player, especially in Trotz's system. He can essentially play anywhere in the lineup and is on an expiring contract. And it shouldn't cost much to get him, probably a late draft pick, fringe prospect or some combination of both.
I know it is tough to stomach by essentially "helping" the Rangers (taking on Namestnikov's salary so they can sign Kreider), but it would probably work out well for both teams. With an expiring contract, Namestnikov could also be easily moved during the season, if Koivula shows he is ready to play center at the NHL level or if another upgrade can be found elsewhere.