To answer your questions...
The Winter fuel blend has been around for a few months now and it's been cold, so that variable is out. My other car has remained constant with the same fuel.
The car has an "Oil Life Percentage Meter", so I changed it at 15% before due, which was 5859 miles.
The plastic "chunks" looked like if you took a heavy-duty, black trash barrel, drug it down the street, and collected the bits of hard, plastic remnants left behind. Almost frayed looking at the edges, but solid to the touch. As for the amount, there was quite a bit -- I drained it into a spouted container that you take to the auto-parts store for recycling, so it has a wide area to catch the oil and a quarter-sized drain hole. I noted the bits in the catch area. In that area, I could probably collect the solid pieces and fill a shot glass (who knows how much is in the container -- possible 5X that much). If need-be, I may strain the container to get the full amount.
I replaced the oil filter with a premium Purolator filter as I have on all of my other cars. The dealer was closed; otherwise, I would have gotten an OEM one. I have the old filter to do a cross-section to see if it was gunked-up, and I saved the old oil.
The engine runs fine and the VTEC kicks-in when expected -- so
RH77