Hi Bipul
Thanks for clarifying your aim. Your general understanding of the basic process seems sound enough.
If you are using Photoshop/ACR or Lightroom to process your raw files, you will need a .dcp profile rather than an ICC profile for camera calibration. (or you can like most people use those supplied by Adobe). Some of the converters such as RAWTherapee (free), Capture One, and AfterShot Pro use an ICC profile for camera calibration.
It's not clear to me what raw processing software you are using, or are you trying to produce your own? If you are, be prepared for a long and difficult development road!
Argyll is fairly powerful and highly regarded although it has a fairly steep learning curve I'd say. It doesn't produce dcp profiles, only icc. The other software you could look at to produce profiles is
DCAMProf. Have a look at this link for some good detail on camera profile creation.
I'm not familiar with the REZ Checker target but you would need to check that it can be used with the CMS software you use.
As for your last question, the camera profile can be used for all images taken with roughly the same illuminant. White balance needs to be adjusted for the particular illuminant for each image. The RAW file EXIF contains details of the WB multipliers the camera selected when taking the shot.
Some people like to have several camera profiles for a few different illuminants. Adobe uses a dual illuminant profile which includes matrices for D65 and CIE A. An interpolated matrix is calculated from these depending on the actual color temperature of the illuminant.
One other source of code for raw conversion is open source Libraw. I haven't used it but it does contain a large number of code modules for various tasks.
Dave