Identify a few disks

[Remark]

I recently picked up a few disks that I am not sure about what they mean.

 

2 are infantry disks that have CAC at the top.  I know I have seen a similar disc at least once before but I don't know what CAC stands for.   I really doubt it is Coastal Artillery Company since it is an infantry disk.  Does anyone know what these CAC discs are?

 

The other I suppose is self explanatory, but I have not seen any similar ones before.  It appears to be a headquarters company disc.  Are there any other opinions on that?

[Major Z]

Not my speciality, but the last "C" is Corps. So, Coastal Artillery Corps. Oddly the discs are not shown on this thorough website, so I'd recommend further research:

 

https://cdsg.org/wp-content/uploads/pdfs/FORTS/CACunits/CACinsignia.pdf

[atb]

With infantry crossed rifles, my guess is school, state force (not national guard), or other type of non-regular organization. I doubt a Coast Artillery Corps connection is there.