-His pronunciation of “geansaí” sounds like “geanzaí”. I’m not sure if that voiced “s” is common in whatever dialect this is.
not the sound, but “geansaì” is a kind of loanword so it has that foreign sound. Actually, everytime I heard that word (even in other dialects, as Ulster), people said “geanzaì”, not “geansaì”.
-His pronunciation of “sin” has a broad “s”. I have definitely heard “anso” instead of “anseo” and “so” instead of “seo”, so I’m sure this is related to that.
that’s normal in Munster Irish: anso, ansan , an rud so, an rud san…