This will apply mostly for an asp.net application where the data is not accessed via soa. Meaning that you get access to the objects loaded from the framework, not Transfer
Please do not use all of the above info such as "Singleton access". You absolutely 100% should not be storing this context to be reused as it is not thread safe.
While informative I think it may be more helpful to share how all this fits into a complete solution architecture. Example- Got a solution showing where you use both EF inheritance and your alternative so that it shows their performance difference.