The CSV files that I downloaded do not seem to have a column or metadata field for the number of likes for a Twitter tweet. Is there a way to how many "likes" a tweet has?
Likes are a dynamic variable not carried in static metadata. To know the number of likes at a point in time, you need to observe the tweet using the Twitter display and record it manually.
Although the CSV file has the number of retweets (another dynamic characteristic) for a given tweet, that is point in time data recorded and sent out by Twitter in their metadata payload. When someone retweets a tweet then they are the Nth person to do it.