Welsh Don's children: etymology

From: João Simões Lopes Filho
Message: 4471
Date: 2000-10-22

What's the etymology for Don's children (Welsh tale) and relatives:
GWYDDION :
AMAETHON < *AMBACTO-NO- "plougher, working man, peasant?"
ARANROD < *ARGANTO-ROTA "silver-wheel"
EFEIDD :  (= EUFYDD ?)
GILVATHWY :
MATH < "bear" ?
MATHONWY :
GOFANNON  (= Irish Goibniu) :  means "smith", but is there IE etymo ?
 
 
Joao SL
Rio