Where spouses separately sell houses in the year they get married (or immediately after for a December wedding), how do capital gains exclusions work? How should we file?

My fiance and I are getting married in December and are building a house set to close next spring. He owned a townhouse that he sold back in March of this year. I also own a townhouse, and we will be putting it on the market soon, hoping to sell it in December or January. So two scenarios:

Assuming my house sells by the end of the year, can we each take advantage of the capital gains exclusion if we file jointly for this year? 

What if my house sells in January (and thus would go on the 2017 return)? If we exclude the sell of his townhouse for this year, would we then need to pay taxes on the proceeds of my house for 2017?