The WL itself has similar percentile thing like Epeenbot. Only difference is that WL is not historical like Epeenbot but it is mentioned that WL percentiles will be historical eventually.
Not at the moment, no. As was mentioned, there are statements on the rankings and percentages of WL that say that a future plan is to have them be historical like epeenbot currently is.
Actually Warcraftlogs already has historical logs saved. You can just search for the person you want at the top search bar and once you found the person you can sort through the bosses and see how the dps changes. No graphical stuff but you can atleast see numbers.