Probably the cheapest and best option is to build more wind and not care too much if it increases curtailment.
Yes, all the things mentioned should be looked into and done when it makes financial sense but "wasting wind" is much less a thing to worry about than "burning gas", and I'd rather waste wind than waste money.
Nope, the difference can be found in the profits made by the company that does in fact own and run the wind farms. The government could capture that should it wish to build them itself. This has been a hot topic recently with regard to fossil fuel energy generators who have been making large profits (in the billions) at the expense of people's energy bills.