I'm so sorry about your mother.
I can't remember the exact fat % in EN and HA, but as far as I remember, either could work.
Vets have suppliers and those suppliers should be able to get you Purina HA or EN. If your vet isn't wanting to deal with it, they can write you a script that you can get filled at another vet's office or online.
Innova may be okay, but that 9% fat is a minimum. You'd have to talk to them to see what the maximum is. In the case of pancreatitis, it may be best to go with a food specially formulated for this. It wouldn't hurt to contact Innova though.
Royal Canin also has a low fat food available.