you read the label
Yes because it would suggest it had gone off.
off white
It will curdle and go sour
you wont get the same taste from using double cream instead of sour cream and the consistency might be a bit off.
Only if it has been professionally fermented in proper conditions, wherein it turns to a popular spread known, unsurprisingly, as "Sour Cream." In any other case, it is highly dubious as to it's health, and should be avoided to stave off indigestion, sickness, or other ill health.
If the skin has gone wrinkley and very soft
Cream cheese will turn green when it is spoiled. It is not like cheddar cheese when it turns green. You can cut off the mold on cheddar and the rest will be fine to eat. Not cream cheese. Once mold has formed, it is best to throw out all the pack.
When heavy cream expires (refrigerated or not, although it will generally keep longer in the refrigerator due to the cooler temperatures), it will go sour. This can be anywhere from discoloring, usually to an off-yellow color, to a rotting or sour smell, and - eventually - congealing and hardening into clumps.
You can , but I have tried it and it did not taste good at all. If you want to you can try, by adding it near the end mixing it in and pulling hte potatoes off.
you talk to them like you talk to your puppy
You failed to provide enough information to properly answer your question. It depends on what you're intending to make. I see your category is listed under poultry. If that's what you're intending to make, the simplest answer to your question would be sour cream. Just be sure to add it last or just before serving so that the sour cream doesn't curdle...the general rule is to take it off the heat BEFORE it reaches a boil. Or another idea would be a can of "cream of" soup (cream of mushroom, cream of broccoli, cream of chicken, etc.). This way you can add less salt and it's a safer choice if you don't want to risk curdling the sour cream or if adding the right seasoning is guesswork or is a hassle for you.
Milk & slice / bulk cheese freezes well, sour cream doesn't. The first two are fine taste & consistency-wise, sour cream was way off on both bases. IMHO I wouldn't think ricotta / cottage cheese would freeze well bc of this. Looks like its time to make lasagna for you!