I wouldn't completely trust the LEED Summary report from EnergyPlus, it's somewhat outdated and in need of some improvements (ref: issue #4588). In particular, the peak demand by end use reports the peak relative to the building's peak, not the absolute peak which is what GBCI looks at. For that, reference the Energy Meters report instead.
As far as I know, EnergyPlus doesn't allow the Summary Reports to be written to separate CSV files and I agree that this would be a great feature to have for streamlining workflows. In the past I've copied/pasted the tabular data I wanted from the Summary Reports into Excel and then linked cells to the LEED reports. Once it's set up the only tedious part is the copy/paste, but that can be solved with some creative measure writing and/or scripting.
See @JasonGlazer's Python script epXML2CSV for one solution. Mine involved writing a Python script that's called from a Reporting Measure.
Update
There is now a OpenStudio Reporting measure.
