Is the money taken from the insurance for replacing a bumper, when it could have been repaired, permissible (halal)? And is what was given to the employee considered a bribe?

Regarding the estimation of damages, it is referred to specialists and regulating bylaws. If the bylaws stipulate calculating the cost of a new collision, then there is no blame upon you for doing so. However, if they do not, and you know that the employee inflated the estimate, then it is not permissible for you to take the excess.

Concerning the employee's request for the cost of a breakfast meal: If it is due to his poverty and need, there is no harm in giving it to him. But if it is in exchange for his work, then this is consuming people's wealth unlawfully, and it is forbidden to give it to him.