Yes, you have right about Vasilefs Konstantinos...this is the correct, but it might create confusion with the already existing BB Vasilefs Konstantinos (of Bretagne Class). I thing Autokrator...separates the two Konstantines!
As for the full name of Vasilefs Konstantinos IA Dragases Palaiologos ...wow that's a big name to spell hahahha!!!
( By the way this a song abt Vasilefs Konstantinos IA Dragases Palaiologos by Stamatis Spanoudakis..."Tha rtheis san astrapi"..."You will come again like a lighting" http://www.youtube.com/watch?v=yOKG0l9DQOk
...if you know the legent about the last King )
Ofcourse there are many King's names of the Byzantium era which we can use...but the Majority of them where not Greeks...
in the other hand none of the last kings of Greece (19th & 20th Century were Greeks in blood) ...so no problem!!!