Oh, this was wonderfully excruciating, start to finish - you made this real, in all its inexcusable behaviour and emotion and pain (both of them, Cecily as well as Richard).

I thought the touch of almost-pity and detached half-sorrow over Edward here was a lovely little counterpoint:

He half-heartedly tried to persuade Elizabeth into giving him her daughter (poor Edward's daughter, dead Edward, his little niece).

and worked amazingly with the acid bitterness towards Clarence.

It feels absolutely like canon!