This isn't really an answer to these specific issues, but there are specific places within the "OpenStudio ecosystem" of software tools and capabilities that you should raise issues like this. If Unmet Hours isn't drumming up enough help for these issues, then I would recommend looking into the following resources based on what's causing the issue.
- Measures (OpenStudio, EnergyPlus, or Reporting categories): The measure's author is the best resource to resolve issues. If the measure you're using is from the Building Component Library (BCL), it should definitely have an author listed.
- OpenStudio Application or SketchUp Plugin: The OpenStudio Coalition is in charge of these two tools, both of which have Github sites with their source code and issue trackers. This would be a great place to request the design return airflow fraction (your 5th item) be exposed in OpenStudio.
- OpenStudio SDK or Parametric Analysis Tool (PAT): NREL is in charge of these two tools, both of which have Github sites with their source code and issue trackers.
- Simulations: Weird errors, warnings, or findings with the DIRECT results from a simulation (not from OpenStudio Results or another reporting measure) can be caused by EnergyPlus (the simulation engine of OpenStudio models). This project is also managed by NREL on Github, where you review the source code and issue tracker.
This kind of positive and constructive feedback is exactly what these open-source tools are looking for -- buy-in from their user community to help make the tools better! It looks like you believe in that philosophy :)
