It's fine as written.
Combining vinegar with baking soda (or any acid with any base) is usually done in baking to produce gas, which can lighten the finished product. This is an icing, which is applied after the baking process; it's not set to capture air bubbles, so any effect would be largely temporary and more easily produced through beating.
The vinegar here is intended to mimic the tangy flavor of real cream cheese. The lemon juice has the same effect, but apple cider vinegar adds a different mix of acids, better matching the flavor of the real thing.
Electric coil is safe on just about every cooking pot/pan you can buy. It's just another heat source.
If a pan has a special requirement, it will say so on the packaging before you buy it.
Regarding a pan to sear meats, you can do no better than a good cast iron pan.
Cast iron will retain it's heat even when you drop a slab of cold meat into it. This makes for better, more even searing. To make things even better, you can then take the entire cast iron pan and stick it right into the oven! No other pan needed.
Personally, I cook steaks in a cast iron pan like so:
1) Take steaks out of fridge and set somewhere to slightly warm up while you prepare everything.
2) Put cast iron pan in the oven and turn it on to 500 degrees F. This will heat up the pan while your oven pre-heats.
3) On a plate, add a small amount of oil (canola or vegtable, not olive oil - you're going to be using very high heat, so you want a high smoke point). In a dish, add Kosher Salt, and pepper and mix around.
4) Put steak on oil plate and turn over a few time to get a light coating. Sprinkle salt/pepper mix to your liking (I personally go overboard on this).
5) Take the pan out of the oven and put it on your stove. Turn on your largest stove burner and set it as high as it will go. Put your pan on this burner to continue heating up.
6) After it's very hot (test by dripping a very small amount of water, it should sizzle and evaporate almost instantly, your coils should be red in color), drop the steak right into the dry, hot pan and don't touch.
7) Let the steak sear on that side for 30 seconds. Flip it once and let is sear on the other side for 30 seconds.
8) Put the entire thing into your oven. Wait for 2 minutes, take it out, flip the steak and put it back in the oven for 2 more minutes.
9) Take the steak out and put it onto a plate with a smaller plate or bowl turned upside down. This makes a slope for any liquids to slide down, away from the tasty seared "crust" you've developed. Cover loosely with foil. Let rest 10 minutes before cutting (very important to keep the juices from spilling out).
10) Enjoy your medium-rare steak!
You can adjust the timings a bit depending if you have a particularly thick cut of steak, or prefer a different doneness.
Be very careful with the cast iron pan, as it will retain it's heat for a long time! Also make sure you use proper care for it, since taking care of your cast iron is a bit different from a normal pan. If you take good care of it, it should last you a lifetime without issues. Some people even hand down their cast iron to their children! Here's some good information: http://www.epicurious.com/expert-advice/how-to-wash-season-and-maintain-cast-iron-cookware-article
Best Answer
If you don't have any turkey, chicken, or vegetable stock or bouillon on hand, I would recommend using all water. That said, without stock or dissolved bouillon, your vegetables will not get the added extra flavor.
I would recommend adding a small amount of salt and/or other seasonings to the water so the vegetables won't be bland. E.g. of others, white or black pepper, poultry seasoning, garlic powder, or a spice blend like Mrs. Dash. Go light, as you can always add more later.
As others have commented, one cup is a huge amount of vinegar. And even a small amount of vinegar is likely to give the turkey an off taste and definitely will hurt the taste of the vegetables.