What is true All those things might be part of the process of application of the scientific method, but there is one 'method.
The scientific method is: one begins with a theory or hypothesis, which might be preceded by research or other process, such as just a 'bright idea' or a guess. Then one would test the hypothesis, commonly by experiment, or by gathering data relevant to the hypothesis. This stage should be impartial. One should not be just looking for data to support the hypothesis, but data to test the hypothesis. One should especially search for data that disproves the hypothesis, since by that means one is likely to strengthen the conclusion if the conclusion is in support of the hypothesis. Tests should include statistical analysis of the results of experiments or data collection. One then comes to a conclusion about the validity (or truth if you like) of the hypothesis, or the probability that it is true. Note that I have not said 'prove', because that implies an absolute yes or no. In most cases for a hypothesis that is supported by this process there will remain that it might be disproved when new data comes to light in the future, which commonly occurs in scientific activity. Disproved, because usually one instance of a hypothesis being untrue would show absolutely that the hypothesis is not true, at least if it was hypothesised that it should hold in all circumstances.
Although this is called the 'scientific' method, I don't believe it should be applied only in cases where the hypothesis might be regarded as a 'scientific hypothesis', which really brings me back to my original question of whether any other process can be used to test whether something is true (or better, probably true) or are all other candidates just the scientific method in disguise.