No worries about being late! You’re right, lots of the names had awesome meanings, I’m enjoying going through the book to find them all.
I just looked for Rhonabwy in the book, it says:
‘Rhonabwy is difficult to parse and it’s origins are obscure; the first element may be Welsh: rhôn “lance”- or even perhaps a form of Rhun- the second may be a corruption of byw “alive”, or mab “son”, followed by the suffix -wy.’
So essentially the meaning isn’t totally clear but could be something like ‘lance alive’ or ‘lance son’.
Hope this helped :)