Probably around 30 sat - just pulled that out of your ass?
Difficulty has nothing to do with the price, just saying. Demand does.
Demand does, and so does opportunity cost. It's easy enough to calculate expected returns from mining this coin vs mining another cryptonight coin (or another algo) and comparing expected BTC yield (or fiat or whatever).
Of course, you'd also need to factor in expected growth/appreciation vs other coins. Price isn't only a factor of demand, but also supply, and miners who were here from day one may (or may not) be inclined to sell at (or below or above) their opportunity cost of other coins.
Exactly. You dont know the demand, and also you dont know how many of the miners will hold. Impossible to tell the price in the short term. Look at signatum for example, insanely high emission for miners and still the price rocketed as hell. It was making more than 50 USD/ per nvidia card in the first days. I have mined many coins that were making insanely high profits per card for extended periods (30+USD) - my opportunity costs were almost negligible and the price was still high.
The concept of opoprtunity cost does not apply here. Its more on what price level are miners willing to sell / how much they see in the value of the project. Daily emission is much more important factor when trying to value the coin.