Jennifer Frazer experimented with frozen coconut milk and wrote about it on her blog.
The conclusion is that you can freeze cococnut milk. The taste is preserved, but the consistency is not.
Jennifer writes:
The thing is, you can still use it just fine for purposes that
don’t depend on coconut milk’s texture or consistency;
Coconut milk is an emulsion of oils in water. To freeze and thaw the coconut milk is enough to affect the emulsion. You can compare the situation to cow's milk. Cow's milk is also an emulsion and the mouth feel will change if you freeze and thaw it.
References:
Don't get frustrated. There really aren't that many variables to keep track of.
1- I don't know the age of store bought yogurt but I have never had just-purchased yogurt not work as a starter. I have had month old yogurt from my fridge not turn out. If you don't plan on making yogurt often enough to keep you starter viable then consider freezing some in ice cube trays.
Whatever starter you use- make sure it lists "live, active cultures". Personally I wouldn't use a flavored yogurt as a starter.
2- I don't think that is enough starter. I will use 1/4 cup of starter for a quart of milk. If you are using 1 cup of milk that would be one Tbs of starter (12X the amount you used).
3- It depends. The goal is to denature the albumin proteins in the milk. 180F is hot enough if the milk is held at that temperature for at least half an hour. It needs to be held at 190F for closer to 10 minutes.
4- You need to get better control of your temperature. 130F will kill your starter but erratic temperature fluctuations will also produce very poor yogurt. Without a temperature controller or manual intervention your slow cooker will get much too hot- even with a water bath.
More successful approaches are to put it in a draft free place in an insulated container, or in your switched off oven.
5- The humidity is not going to play a role unless it is condensing into your container enough to dilute things.
Good luck. I hope you get it working. Fermenting milk is fun.
Best Answer
There are two choices when flavoring yogurt: while you are making it and after it is made. If you want to make a batch of yogurt and choose your flavors later you may enjoy adding coconut extract (or other extracts) after the fact. However, if you are set on a single flavor (as your question implies) you will get better results adding a flavoring oil, the chemistry of oils vs. alcohol seem to react differently. Check out the "Mr. Yogurt" link, he has done some experimenting that will help you along.