[US airport] to DUB questions for older people.

My sister (LAX) and I (AUS) are looking to visit my grandson at UCD in Dublin sometime around late March/early April. Haven't traveled international in a while. It would be nice (but unlikely) to take Business, but we'll want at LEAST Premium Economy. And as few stops as possible.

There are no direct flights (I can find) from AUS (my home airport) to DUB. Would it be smarter/cheaper for us to meet for a direct flight from somewhere else in the US? [LAX (where my sister lives) would be a LONG flight, but maybe that's one option? And how does BA and EI factor in? They're still point buddies with AA, right?

FWIW: We each have Gold Status (I don't think that means much these days) and each have around 80-90k AAdvantage miles.

PS (Is there a compelling reason to avoid going through London? Seemed like the last time I flew from US to Dublin, I had to retrieve bags in Heathrow and go through Customs twice (each way)? Maybe that's changed?)

Thanks for any info! I appreciate this sub.