You are making your question very complicated and misleading by referring to it as an EBS/AIB mortgage. There is no such thing.
If you have consequential losses as a result of not been given the AIB prevailing rate tracker, you can ask AIB for more compensation. And if you are not happy with the outcome, you could go to the Ombudsman or the High Court.
You have not provided any numbers.
But if your EBS buy to let property was not sustainable, it was not sustainable.
It seems to me to be a bit of a stretch to say "Well if I had a cheaper mortgage rate on my home loan, I could have kept the buy to let".
EBS, along with most banks, was very flexible in rescheduling mortgages. If they were not able to reschedule your buy to let, it was because you did not have the payment capacity by a fairly wide margin. I doubt that having a tracker on your home would have made it sustainable.
Having said that, you should make the claim and AIB, the Appeals Panel or the Ombudsman might agree with you.
But don't rely on it.
Brendan