Well explained answer, K. One other thing I would add is that how the DI is done depends greatly on budget. A lot of facilities will bump the entire project up to 2k or uncompressed HD for DI work just before the filmout. That's what DigitalFilm Tree does for example. It might be worth contacting them or a similar facility for workflow and budgeting recommendations.
http://digitalfilmtree.com/
Noah