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.
1) a lot of wind means there's too much power... that has to be used somewhere, that's why you have negative prices, to get someone to take that power off the grid and use it for something, sometimes useless, and someone has to pay for that
2) no wind means you still need gas, hydro, nuclear etc. powerplants, because you need power even when there is no wind and sun, so you need all the power generating capacity covered even without wind