For all things related to licensing, check with your IBM Client Rep.
Generally speaking, ODWEK is included under your existing licenses, and there's no restriction on the number of ODWEK Instances you need. Also, you don't need to configure the CMOD server in order to run ODWEK.
Also, it's not advisable to try and split ODWEK from the installer packages - there are common libraries shared between CMOD & ODWEK.
-JD.