Possible Olympus FF dilemma....what will they do?

About the 4/3 -> m4/3 scenario? Highly unlikely IMHO.

4/3 vs m4/3 had the same sensor size, the same user base, more or less the same potential clients, nearly the same market.

m4/3 vs FF is different formats, different potential clients, two different markets. Two markets that make sense to evolve together, much better than APS-C and FF.

What is sure is that there's only one player mirrorless FF now : Sony. So it's a growing market where every major camera makers will play in the future decade. Common sense will say better sooner than later.

The second thought is that the two Big Boys (Canon and Nikon) are in a difficult position : a mirrorless FF line will eat their DSLR line sales. Olympus (and Panasonic) don't have this problem.

But of course, only Olympus knows.