[Hope]

So can you change the Shahada and add in other prophets? Is this allow?

At the moment we have people following three prophets.i.e Moses, Jesus and Muhammad.

 if people want,they can add Moses or Jesus.However they must make sure which scripture they want to follow after conversion.

People add other prophets name seldomly.I believe it is as per the request of the convert or the ignorance of the Muslim witness.