I speak some Irish, and I'm interested in leveraging that knowledge to acquire a passive understanding of Gaelic. So I'm particularly interested in the points of difference between the two languages.
One thing I want to confirm is that Gaelic has no equivalent of the Irish "functional genitive". When Irish has two consecutive nouns in the genitive, the first doesn't inflect as expected. It is lenited but there is no slenderisation, vowel change, etc. So, for instance, tigh an mhic "the son's house" but tigh mhac Sheáin "John's son's house".
Examples like Taigh Chaluim Nèill Òig lead me to conclude that this construction is unknown in Gaelic, but I'd like a definitive word on that.