Currently, Draft will find the OCIO path if it is set, or look for a config.ocio if it isn’t (first for included configs, then locations in PATH), or you can specify OCIO using a function call. Once OCIO is set, I’m assuming people would actually like to use the LUTs? 
Following the pattern we use for other LUTS, I’ve added CreateOCIO (takes two colorspace names defined in config.ocio), CreateOCIOFromRoles (takes two role enumeration values), and CreateOCIOFromColorSpace (takes the name of a colorspace, the direction of the colorspace, and the desired direction of the transform). From the “lut” created using one of these methods, you can Apply it to images, or get the Inverse.
There appears to be a bunch of stuff in the API meant for generating config.ocio files.
From what I’ve described, does it look like I’ve covered your use cases, or have I missed something?
Cheers,
Andrea