What is exactly considered as mocking the religion. Is this new 'Say Wallahi Bro' trend considered mocking

Only a person who suffers from waswas would ask such a question. Therefore, I think what you should be paying attention to is not what is considered to be mocking the religion—so that you don't obsess over it with OCD thoughts—but how to cure waswas. That should be your main goal. For further benefit (and please do not misunderstand the tone to be something negative, because it is not), there is nobody who doesn't know what mockery is. If somebody were to mock you, you would know it. But because of OCD, you start saying, "I do not know what would be considered mockery." Mockery is mockery. Everybody knows what it is: something that is demeaning, making fun, and so on.