Praise be to Allah.
With regard to taking the Mus-haf from the mosque, this is not permitted, because the Mus-hafs of the mosque should stay in the mosque and not be taken away.
With regard to elongating the back excessively during the prostration, this is not appropriate. Rather the back should be moderate when prostrating, not stretched out too much and not bent too much. The back should be moderate with the arms lifted up off the ground and the elbows away from the sides, and the stomach lifted up off the thighs, i.e., one should follow a middle way, not stretching it or bending it too much.
With regard to raising the voice when reciting Qur’aan before the prayer, you should not raise your voice if there is anyone else present, rather you should read quietly to yourself, so as not to disturb other people or distract those who are praying or reading Qur’aan. But he may raise his voice a little.
With regard to playing with one’s beard or clothes while praying, this is makrooh. The Sunnah is to remain still. Allaah says:
“Successful indeed are the believers.
Those who offer their Salaah (prayers) with all solemnity and full submissiveness”
So you have to be solemn in your prayer and not play with your beard or clothes. A slight movement if necessary is forgiven, but a lot of movement is not permitted unless absolutely necessary.