I think those high grade samples could be amblygonite. In theory...

I think those high grade samples could be amblygonite. In theory amblygonite should be relatively easy to process, more the question is how much of it is there? Only very rarely forms economic sized orebodies. It doesn't look like any sort of mica, which is a plus. MOX shoot themselves in the foot however by going on about the lepidolite mica (rubbish IMO)
My advice would be to focus on clarifying the mineralogy of the high grade samples and then get a feel for how much there could be.