As as been said by others, nothing has changed. If your previous flights with Aer Lingus were with an EI code they would not qualify before and would not today. If they were on a BA code before or now they would qualify.

For your AA flight, if your confirmation email says you are on AA1234 it also won’t qualify, if it says BA5678 it will. (Unless of course AA1234 is actually itself a BA plane)

Tier points are a slightly different matter from qualifying flights and Aer Lingus has been added to Tier point earning recently. AA always has been.