1. Since you have got bail from the court the first hurdle has been crossed. The proof which you presented to the police should have been considered by it, but the way police functions in this country is a far cry from the manner in which a police force must function. So do not rely on police to lean in your favour.
2. Legally speaking, you can file a case for defamation against him, but it should be done only after your brother is exonerated by the court. Filing a counter case at this juncture can be highly counter productive.
3. The proof which you have in support of your brother should be produced in the court to rebut the case of the police. The court will consider every evidence in a careful manner. Police may not hear your version, but the court will.
4. If he files any fresh case against you then seek anticipatory bail immediately. Alternatively, you can move the High Court to seek protection against fresh false cases.
5. Contest the case on merits. In consultation with your lawyer explore the possibility of applying for quashing of the case. The agreement entered into between your father and her father has no value in the eyes of the law.
6. If held guilty your brother may not be able to find any employment. Furthermore, he may be denied passport and/or visa.
7. The girl and her family is in the driver's seat, so they wont take the case back. Concentrate on proving your innocence on merits as the case has now reached a decisive stage.