What you suggest will work, but it is not necessary.
You can file joint returns for all of the years at issue. The home sale exclusion can be used on a separate basis even if you file a joint tax return.
You can use your 250,000 dollar exclusion on the sale of your home on your 2017 return (make sure you indicate that you are the only owner and only one that qualifies for the exclusion on the sale of your home). Your wife can use her 250,000 dollar exclusion on the sale of her home in 2018 or 2019 (make sure you indicate that your wife is the only owner and only one that qualifies for the exclusion on the sale of your home). After the sale of your wife's home, you cannot have a home sale exclusion (for a home you own jointly) until two years after the tax year when you sale your wife's home.
Filing separate returns results in a less favorable tax outcome in almost every situation (I have never seen separate returns result in a better tax outcome than a joint return in my 12 year career).
