Looking good so far, mate. The only real inconsistancy I can find is that 'Merlin' was actually a title, refering to the upper-councils of Druids. Taliesin and Myrddin were both 'High Merlin' at some point or another.
Anyway, that's the only nit-pick I have. Still reckon it's Perce!
True Merlin was a title, and very good on recognizing Taliesin as another who carried that title. However Myrddin Emrys was the one before Taliesin and his name was passed down to Taliesin wehn Myrddin left for Bardesy Isl and Clas Myrddin.
It was the French who change the name to Merlin due to pronunciation having it sound like Merdin which based off of merde, well... that didn't go over well, so the spelling was changed.
Current unidentified DE theory: Percy.
We'll see how good I am later.
Author's Response: We shall see, now won't we.