2. "How to compensate the homestead for occupying my grave?" ：
(1) It is true that the grave belongs to your family, but the land is no longer yours: although it was distributed to your family before joining the society, it was redistributed to other villages after joining the society, and the ownership of the land belongs to other villages, neither your village nor your family, regardless of whether the grave is flat or not.
(2) Compensation is really hard to say. You can consult the local government documents or the Civil Affairs Bureau for details. As far as I know, the country does not support the construction of graves at present. In most areas, it is required to level the graves without affecting the use, and it is also possible to move to the cemetery.
If you are interested, you can watch two recent CCTV programs. There is a real case about the cemetery in Pinggu District of Beijing being in someone else's mountain: the current mountain contractor demands to move the grave and compensate the grave (asking the grave owner to compensate the land user).
3. However, if the other party hurts your family in the conflict, you can report the case to the police and apply for injury identification, so that you can be held accountable for intentional injury; Criminal responsibility and civil responsibility shall be investigated for minor injuries and above; Minor injuries should be investigated for administrative responsibility and civil liability for compensation.
4. Suggestion: If possible, try to negotiate with each other and ask for a certain compensation before turning over your grandmother's grave. Otherwise it will be inconvenient for others to build houses in the future. In addition, as far as the current national policy is concerned, your family is unreasonable, and it is unlikely to be supported by the court: the other party has the right to decide how to use the collective land of the other village, but your ancestral grave will not move. Remember that according to the national policy, the grave should be flat and not affect the other party's use, and the other party should build a house.
Good luck.