I bypassed the filter. For what it worth, the fittings did indeed turn inside the pex pipe and I was able to just unscrew them from the filter. I then put a 1/2" threaded union on to complete the bypass. All looked well at first. After a few minutes there was a small, slow leak at the pex clamp fitting. Maybe it was a leak before, but I am guessing it had to do with me twisting/turning the fitting to disconnect form the filter.
Went to Lowes, got sharkbite 1/2" coupling, cut the pex, installed the coupling. All seems well now. Here is a pic. I had not installed the filter canister again when I snapped the pic.