if younger speakers are using standard Irish with English phonetics would that not indicate that they are learning their Irish in school and not in the home/community ?

I dont know why all or most the teachers in and near any gaeltachts are not from that gaeltacht or at least proficient in its dialect.
They could still teach standard Irish along with the dialect ?

Unfortunately, there are some “Gaeltacht” areas where hardly anyone is a native speaker of Irish. In real gaeltachtaí like Corca Dhuibhne, CF+Conamara, and Northwestern Donegal, kids learn Irish speaking with their parents, just like almost all people learn their native language. Then there are some areas where that is not the case, and the parents pretty much rely on the school to make sure that the kids learn Irish. Past of the West Cork Gaeltacht definitely fall into this category. Having said that, I have met young native speakers in Cúil Aodha who are indeed true native speakers. Though I would be surprised if many kids in Baile Bhuirne speak Irish at home with their parents.