Hello

I was wondering is there any way to change cas item arrangement?
For example most bra ccs are arrange in the same bra group/arrangement but I noticed some items dont quite appear in their group, is there any way to fix or edit this?

There are a few ways to manipulate CAS either with hiders or Dresser Mod.
Dresser: http://nraas.wikispaces.com/Dresser
Hiders: http://simborg.tumblr.com/tagged/hiders/chrono

The Dresser Mod has is a great mod and offers most of the options you seek. Many Simmers use it to blacklist items in CAS. However in my experience and seeing threads posted by others looking for help Dresser could also impact other CAS settings unfavorably. A more user friendly option would be to use Kuree's EasyCASP Editor
(I do not believe it will work with patch 1.69)

You might want to consider trying Master Controller first. It has lots of options to arrange all types of items in CAS. They are listed Here on the FAQ Page

If you would like further help with either Dresser or Master Controller please feel free to post over at NRaas Chattet Box . Most of the members are familiar with both mods and would be happy to help you further.

I already tried CASP editor before and as far as I know it only limited to sims3pack installed CC, is there any program similar but can also read packages files?

I have edited package files using S3PE. There are instructions for using S3PE in NRaas Blacklisting Document. I do not use Dresser but #2. Collecting CAS-parts to block within the page has instructions to edit with S3PE. For the most part I use The settings in Master Controller I identified in my last post to edit.

I'm sure other's in here will also share some of their methods.