Everclear works. Cheap and high alcohol means it stays free of contamination for longer. Plus, if you get any suckback, no worries as 1) it's clean, and 2) you're making alcohol anyway, and 3) it has no taste.
By most accounts of people who seem to know about these things, heat makes wine age faster, but not necessarily better. Take from that what you will got your specific situation.
Sounds like a group effort. OP wanted to use commercial yeast, but partner vetoed and forced a wild fermentation.
Sounds like the partner is getting very interesting advice.
Oops...didn't see the last few posts. Glad bottling went well, and it seems to taste good.
If it tastes good, why mess with it? At least do a trial if you're really wanting to do something.
And it's already aged 7 years, how much longer are you planning to let it sit in the bottle?
Sure. Breaking the cap is always necessary. My point about a loose cover was meant to be in contrast to an airlocked carboy. One assumes stirring to drive off CO2 and punch the cap. I wasn't intending to generalize about processes in larger operations like you showed.
Like others have stated, I think you'll find that overkill for most wine. Some whites do better with a bit of oxygen up front and then getting airlocked, like beer, but most reds prefer less oxygen up front and more slowly throughout (that's what the loose cover gets you). Don't know for sure...
As in brewing, you always need to think about how much oxygen to introduce. Stirring introduces some oxygen, but not much. What wine are you making, and how were you oxygenating you wort?
After 7 years, any yeast present in there is dead. It's possible to introduce something new at bottling time, but how likely that is depends on a number of factors. What was the OG?