Surely there is more to this question. Isn’t the obvious answer, to go home, get your hat and jacket, and daven with the next minyan?
Correct. The question assumes that there is no later minyan available.
Although I would personally wait for my hat and jacket even if it meant davening b’yechidus (as per my R”Y, an adam gadol and posek, who told me so), there are certainly grounds to argue. Either way, you are correct that according to all of the opinions mentioned, one would be required to go get his hat and jacket and find a later minyan, and not daven at a more convenient minyan without his hat and jacket. Tzitz Eliezer, however, has grounds to be meikil further, based on the fact that it is no longer typical to wear a hat in front of a human king.