So, if I understand you correctly, your wife medical expenses could not be reimbursed from your FSA until December? In that case, she was eligible for the HSA until December.
NOTE, eligibility is determined by the coverage on the first day of the month. If your FSA became active on December 2, then your spouse was still under the HDHP for December as well.
This means that when your spouse indicates here HDHP coverage, instead of saying "no, I did not have coverage", you would say "I had different types of coverage at different times of the year." The next screen will ask you for the coverage month by month. Put Family for any month in which she did not have access to FSA funds (she was the one with the Family HDHP coverage, right?), and "none" for any month in which she could have been reimbursed by your FSA, always looking at the first of the month. This should make for quite a difference.
