Because you're limited, you might as well go for the PBB, it does more than the PCA and
PCL.

The B65 is a horrible ship, but it does have yamato supports.
The Asama is fun at high (lv 100+) levels, but it's horrible otherwise.
PCL...useless.

If you got other nation crews, you should go for one of the others, as IJN premium ships
generally suck.

If i were you id go for USN PCL and PCA and roll a USN CV crew (or buy RN PCL/PCA and roll
a RN BB crew)

I bought the Asama and i'm not too happy with it. I think i had more fun with Mogami CA
(with 8' for Blits and 6'1 N with HHE and AA for GB) but if you want to do both AA and
shoot rushing DD and FFs with 14" shells the asama is for you..

Never used the IJN PBB but i have heard it has a horrible reputation.
It looks like a Yamato so you draw unwanted attention and is generally not too good at
anything other than AA.

I'd say go for the PCL and PCA,

Unfortunatly I only heard about this game in the middle of December, so the
maximum amount of coins I can earn is 16.

Is collecting enough coins for the Haruna or Hyuga an option?

The Dhonburi is a toy (a fun toy, but still...), with no more crew space than any other
CL. It can carry enough belt to be iffy against 8" HE. Firepower is very limited (worse
than the Agano), though the FCS, size, and gun options make it possible to concentrate
what you have rather well.

The Asama is meh, with serious spread issues at-level on the main guns (4 shell salvos
!=fun), and limited AA. With 4.7" duals, it has a lighter broadside than the Mogami/Myoko
with 6.1" trips. Also, mind at-level* spread issues, a gap in the T-slots, and low shell
damage requiring several hits for most kills (mitigated with the Mogami/Myoko). With the
3.9" As, you get decent damage and a good rate of fire, but somewhat bad range. (Compare
with US 5"/38 N, or 3"/70 N/D. The Asama has a vague similarity to the Pensacola here)
Dual 3.9"/5" NLD options are limited by the small T-slot size. It is, however, a CA with
BB1 crew space, can use any level 52+ IJN sailor as a BO, and the above mentioned AA does
work (if unspectacularly).

I am mainly familiar with the B65 by reputation, and will leave a discussion of that to
someone like Angus725 or Boom21.

*One "shouldn't" have at-level IJN AA gunners.