Welcome to the forum Michael! I'm so excited for your Camino, it's going to be a blessed experience.
2130 is pretty late and if traveling on a Monday then I would definitely advice getting a room in Biarritz or Bayonne. From my own experience the last train out of Bayonne on a Monday is 18:06. Getting to St. Jean is always the hardest part but no matter how you plan it, it will be the right plan for you.
I had to give up my bed at one of the alburgues because I didn't arrive on time for dinner and that was a requirement for staying there. Anyway, my first night on the Camino in SJPdP was in an attick of an alburgue that was full. I shared the space with another pilgrim, he was from Ireland, a complete stranger. It was the best first night anyone could ask for. An amazing experience.
Buen Camino and may the Lord guide your steps.