Science experiment or Cider?

Did a primary fermentation in wine jugs and racked after about 9 days. Used two different strains of yeast from the home brew store. (I can't remember the names, one was a yellow packet and the other was a red champagne yeast I think)

I tasted each, the yellow was good, slightly sweet. I cut into it with some bourbon and back sweetened with splenda. The red champagne yeast bottle was relatively sour (if not a touch vinegary) but tasted more champagne-ish. I cut into that with less bourbon, some nutmeg and cinnamon, and back sweetened with splenda to taste.

I re-installed the vapor locks to bottle condition for two weeks. (I'm fine with it being still and I was uneasy about carbonating them while they sit in my bedroom)

Now the one that tasted sour has a layer of white dots forming suspended in the top cm or so which worries me("photo").
The other one has a few (maybe 10 or so) little floaters that may be dead yeast colonies floating on top.("photo (1)" & "image")

Need help... did I make cider, cider-vinegar or worse?

Thanks!

Well hello there. This experiment is right up my alley so to speak.

The yellow pack was probably Danstar champagne yeast, that's a pretty good/strong fermenter.
The red pack was probably Montrachet I think, not ideal for what you are doing, slower fermenter, less alcohol tolerance.

Vinegary taste may be acetic acid bacteria taking hold (acetobacter) which is generally not really good unless you're making vinegar.

At 9 days fermentation may have not been complete. These things are going to taste rough at best right out of primary fermentation, a minimum of 30 days aging is needed to make them barely palatable, and even then they'll be rough around the edges / fusel alcohols etc.

Splenda / artificial sweeteners I don't know, I don't like those they always seem to have a bit of bitterness to them so I never use them.

If it is bacteria taking hold should I hunt down some campden tabs tomorrow and throw one in each just to be sure?
I have a beer fest on Saturday and I'm hoping to be able to try some of these with friends... hopefully without sickening them in the process haha

Personally I would not put campden in it, at least not this early in the game. There is supposedly more risk in not sanitizing each and every implement and ingredient before use but I have not seen that in practice yet anyway. I think your brews are simply too young still. If you didn't have the one that's getting vinegary airlocked tightly after the first few days of fermentation that might lead to acetobacter (acetic acid) bacteria getting hold. If you simply keep it very cold, just above freezing, that will stabilize it a bit anyway so it can age. I think if there's really anything nasty growing in there, the smell and taste will be so nasty that there's no way you would drink it anyway. Those commercial yeasts you pitched are pretty dang competitive too, even against wild yeasts, so that should help.

And just to note, planning a tasting only a couple weeks after starting means some of those people may not at all like the taste, unless they're purely interested in the alcohol effects and not at all worried about the taste. it will be 'rough around the edges' at best that young. Some people don't mind or even like it that way, but most people who are used to commercial brew are not going to like it.

The whitish specs floating may just be the yeast, I see that sort of thing happen with many of my brews when the near the end of fermentation. Eventually they usually sink to the bottom themselves.

I appreciate the help! I capped them and threw them in the fridge last night. I'll let you know how they turn out at the beer fest

That sounds good, I hope it goes well! If they can get some aging under their belt they will probably smooth out pretty nicely.