For the Dharmaguptaka Vinaya, someone guilty of a pārājika is unmistakeably still a bhikṣu. If sincerely remorseful, he can ask for the life-long probation, which is granted by jñapti caturtha karma. He is stripped of the 35 privileges and takes his seat between the bhikṣus and the śrāmaṇeras (or between bhikṣuṇīs and śikṣamāṇās if she is a bhikṣuṇī). All the Vinayas except the Pāli Vinaya accept a form of lifelong repentance.
Please, refer to the volume Bhikṣuṇī Training – Pārājika, p. 24, for a thorough discussion and an examination of the sources.
The difference is based on the intention. If the intention is to have sexual intercourse, all the preliminary actions are considered a preliminary step of pārājika 1. If the intention is to have a certain level on intimacy that allows for physical contact, but there is no intention of going as far as having sexual intercourse, the offence is pārājika 5. If one simply desires to spend time with one’s beloved, walking hand in hand, etc., but does not has yet any intention to go beyond this, the offence is pārājika 6. Therefore, the bhikṣuṇī who is called to assess the offence has to investigate clearly the motivation of the offender.
See also Bhikṣuṇī Training – Pārājika, p. 153.