* wine is a traditional food preservation system. The first level is stability is preventing growth of things that make one sick. By having the pH in the range where grapes are you don’t have to worry about pathogens.
* Alcohol is also toxic and early in the process effectively kills bacteria. If exposed to air surface organisms can grow and the normal one will produce vinegar. ,,, you may have made salad dressing or marinade, but again not toxic
* oxidation reactions produce a variety of off flavors. Which flavor depends on how fast the oxygen is added. Slow addition will produce sherry like flavors. Fast oxidation/?lots of oxygen tends to produce burn in the back of the throat swallowing and basically the wine is considered spoiled because of the flavor.
* filtering? This is cosmetic. Home filter options frequently add oxygen which pushes toward creating off flavors. If you have factory grade pumps and sealed tubing/ filter housing, ,,, yes it can be done. Filtering and consuming within a few days works well.
* fine lees don’t really hurt you. Fine lees would be mostly yeast that came out of solution. Again cosmetic.