One cider too dry + one stuck fermentation = blend?

First here's what I wanted to do to make two sweet ciders:

Batch A: Cider from Twin Creek Farms, PA.
Rather sweet, OG 1.061.
Wyeast 1332 NW Ale.
cold crash at 1.010

Batch 1: Cider from Distillery Lane Cider Works in Jefferson MD.
Pretty tangy with a 1.052 OG.
Wyeast 4184 Sweet Mead yeast
cold crash at 1.010, rack off the yeast and add malolactic cultures.

Both batches fermented at 65 F.

My friends had the same cider from Twin Creek, but a carboy of unpasteurized from Distillery Lane. They tried to kill the wild yeast in the Distillery Lane. However the campden tabs just apparently made it mad and the wild yeast took off and rhino-gassed their basement. What a distressing smell.

The original plan was to do a bit of a yeast experiment, and have fun trying to taste the differences, but it seems things have gone awry.

Batch A of mine seems to have stalled out. It had a very slow ferment, going from 1.061 to 1.030 in 10 days, but has been stuck at 1.030 for the last 4 days, even though I am getting very slight airlock activity. Currently it is overly sweet.

Batch 1 overshot the target. It went from 1.016 to 1.004 in 24 hours. I came home from work on day 10 and when I went to measure the SG the cider had already dropped bright. So instead of a sweet cider, it is pretty darn dry, and continuing to get drier after I added the malolactic cultures and I let it sit and I hesitate over what to do about it. It doesn't taste bad, just dry and a bit tart.

I was thinking... what if I cold crashed both and blended the batches together? The initial experiment is pretty much out the door now because of the wild fermentation of the friends' batch and my overshooting the target SG on mine. The malolactic culture would be pretty much wasted, but I thiefed approximately equal measures of both and mixed them, and I think the sweetness of the Batch A cider balances out the tartness of the Batch 1 cider. It actually tastes really good as a blend.

Also, on cold crashing: if I am very careful not to pick up the yeast I should be able to bottle without creating bombs, right? Or do I need to kill of everything with some sulfates?

Blending sounds like a good idea to me. Afterwards, I would wait a week or two before bottling or anything to make sure the gravity doesn't keep creeping down (the dry one might perk up the stuck one, for example).

You don't necessarily need to kill off everything if you're sure that fermentation is done. But if you want to play it safe, stabilizing isn't a bad idea.

Crap. I got home this afternoon and pulled two samples. The Batch A was still stalled at 1.030 so into the fridge it went.

Batch 1 had a distinctive smell of vinegar. I hit it with campden tabs and threw it into the fridge as well (bad idea?), hopefully I caught it in time. It only has the faintest taste of vinegar behind the apple tartness, but the smell is definitely there.

Oh well, we'll see if I caught it in time, otherwise I may end up making 5 gallons of homemade apple cider vinegar. Not nearly as much fun to drink.