I know in German 'Bloe' is pronounced like 'blay' (it's the start of my family name so personal experience lol) and the Japanese like to play with German names and words.

So with the name Merlwyb Bloefhiswyn, I think the last name might be more pronounced:

Blay-fiss-win

or

Blay-hiss-win if the F is silent as some think.

I'm saying the first name pretty much like everyone else is, heehee.