1) It is obligatory for a Muslim man, born into Islam or converted, to be circumcised in general. There are no shar’i requirements other than to believe in the oneness of God, the messenger Muhammad (sawa) and the other tenets of faith. This is what makes you a Muslim and makes it permissible to marry a Muslim woman, whether she is sayyid or not.
2) It can be done after, but should not be delayed. It is only a requirement for tawaf