You can run SS FCS since the FCS doesn't matter for torpedeos and save a few hundred tons. Engines don't effect torpedeo top speed as far as I know. You want the (Heavy) engine that requires the most engine room space (The kitakami can hold up to a 150 engine) and that is the CL Engine I (Heavy) you have.

Otherwise theirs not much you can do to change your top speed and since the kita doesn't have much displacement you can't really add any high level engineers to it.

Like with any ship you need to have engineers.  You can have up to 3 engineers - increases speed, overheat speed, and overheat time.  They also contribute restore/repair ability.

well there are more setups than that...
minewhore:
10 mine launchers loaded with 51 mine each, ss 1 fcs.

aa whore setups:
10x single 4.7" DP guns (longest range)
10x dual 4.7" DP guns (long range)
10x dual 3.9" DP guns (real dual purpose guns and spam guns combo)
10x dual 3" DP guns (spam guns, shortest range)

also there is HH setup...