Actually, Owen is married to pannas.
So gŵ?r = husband and gwraig = wife ?
Yes it is the emphatic structure which we use when saying that something/someone is something.
The same as when we learned to say things like "Mecanic dw i" and "Dewi Lingo dych chi" earlier.
May be Pannas is Owen's wife's maiden name?..
Because this is an emphatic sentence i.e the most important aspect of the sentence is placed first for emphasis. In this construction "ydy" is the verb "is" and it replaces "mae".
Could I say "Mae Owen yn fy ngwr." and still have generally the same meaning?
No, not here since (and I can't remember the fancy word for it) this sentence is used to equate one thing to another thing i.e that "Owen" = "My husband" therefore you need to use the emphatic construction here.
No, Ng is the same as the English Ng except the g is not repronounced. The audio sounds normal to me so where have you got this idea from?
Since the whole point of this structure (A ydy B) is to indicate an identity between A and B, surely this sentence can also mean "My husband is Owen"? In fact, isn't that more likely to be the case, since in identification sentences Welsh normally puts the important/new information of the left side of the equation, English on the right? (Prifddinas Cymru ydy Caerdydd = Cardiff is the capital of Wales) versus (Caerdydd ydy prifddinas Cymru = The capital of Wales is Cardiff).
"Owen is my husband"="Owen ydy fy ngŵr (i)". "My husband is Owen"="Fy ngŵr (i) ydy Owen"
Yes, but there you're talking about focused rather than identification sentences (even though those happen to be identification sentences too).
In focused sentences the element that is being focused upon comes at the head of the Welsh sentence, and does so even in non-identification sentences.
Thus, Ar y bwrdd mae dy frecwast (di) = Your breakfast's on the table. (Here I have used bold to indicate the emphatic intonation that is used in English).