Yes, there are 19 days left, but there are 4 bills on the floor for vote and the next 4 won't get debate time until the 26th. This means 7 days debate time (January 2nd) plus 7 days vote time (January 9th) which goes over session.
You are mis-reading the SPR on this issue. Whilst there can only be 4 bills being debated at any one time, there can be as many as the Senate wishes being voted upon.
Yesterday we saw 3 of the amendments on your list enter debate time. There is still time for them to receive full debate and voting time before the end of the session.