He wouldn't want any of them here, but if he had to chose, it would probably be Sorata. He trusts all of the Seals to be able to handle themselves, but Sorata has always struck him as the best able to handle all the many and varied things life throws at him -- and he would be good for Subaru, too. Probably also TRC!Kamui.
Was there a member of the government building group that Kamui particularly liked? Or what there anyone in the Tower group he didn't despise?