BB, I am happy for you to be preparing to celebrate the holidays in a safe and sensible way that will work for you and your loved ones! I can imagine that you will probably shed some happy tears, because I remember, my holiday after my own transplant. My transplant was in 2009 when I had a liver and kidney transplant at Mayo Rochester. My advice, should you want it, is to use common sense and be prepared to say "no" when you feel uncertain of the safety about going to any event. It does take effort and with time and practice, will become a natural instinct.

In response to your question about a cold, I have learned to listen to my body, and when I feel a cold coming on, I begin to take preventive actions. For me that includes getting extra rest, staying hydrated, and reducing unnecessary activities/obligations. I also monitor my temperature and have seek medical advice if it goes above 101.
Over the counter medicines that are safe (per my transplant notes) include Tylenol, Sudafed, Robitussin, and Benadryl. Never go above the daily recommendations.

Here is a discussion with members sharing their experiences.
Living Life after your Transplant
https://connect.mayoclinic.org/discussion/living-life-after-your-transplant/
Happy Holidays!