Basically yeast nutrient is an assortment of nutrients (phosphates, urea, minerals, vitamins, etc) that keep the yeast healthy and out growing foreign organisms. The urea is rich in the elements for forming amino acids and the phosphates are used for forming phospholipids that make up cell walls. A carbohydrate, like molasses, won't be the same. Yeast nutrient is geared towards yeast cell reproduction. I've brewed wine without it, but it can get a bit of an off flavor from foreign organisms or too slow of fermentation.
I recommend you read this article about yeast nutrient:
https://beerandbrewing.com/what-exactly ... -nutrient/If you are thinking about using wild yeast or baking yeast, then you are not concerned about flavor. Wild yeast is a huge gamble with the flavors and strength of the final product, and it is highly possible that vinegar forming bacteria will be introduced along with the wild yeast. Baking yeast makes a foul smelling and tasting brew, in my experience. I've had wine and beer made with baking yeast, and both have an off, almost cough syrup flavor. If you want to brew wine that is good, I highly recommend that you invest the $1 in a decent quality yeast. I think that the red star wine yeast is about $1.20 at my local hardware store. They also carry yeast nutrient for about $2.50.
When I spend the time and invest in the fruit or grain to brew, I want it to taste good, so I often use a specific yeast culture, temperature control, etc.
One item you didn't mention is sulfites. These are often added to wine, and I find them to give the wine a rotten egg flavor and aroma, causing one to get red and flushed after consuming. I advise not adding sulfites to your brew. It is often marketed as campden tablets that contain potassium and/or sodium metabisulfite. Wine already will have naturally occuring sulfites and doesn't need any more added.