I think this is the most important.
But I think about this part you might to think twice.
And no, it’s not expected that phonak will do MFI (nor is that that easy to do as you think, plus different levels are same hardware just some software switch to give or take features, whereas MFI from what I gather uses different chip than regular BT does, so, it’s hardware issue then, so that makes it basically having 2 has, which would probably drive costs even higher, since they’d need double teams for research and development)
What is the future is what I said, every manufacturer will support that new BT standard that’s coming, but it will take some years until they first invent the standard (I think they’re close?), then phones start implementing it, then they’ll do aids that support that when there’s financial reason to support that. I wouldn’t expect seeing HAs that have something that only few phones have.
What I mean, if you want to wait for phonak to support mfi, you might not see it in your lifetime.
The future is platform independent connection, so it makes no sense to invest into MFI just to abandon it when this new thing is around the corner.