Short, direct answer:

• Yes, a sanyami (one with full vows) can have krishna, neel or kapot leshya – but only in the 6th gunasthana.
• In the 7th gunasthana (apramatta-samyat), these three ashubha leshyas cannot remain.

A bit more clearly:

1. 6th gunasthana – pramatta-samyat

- Here the soul has full vows (complete sanyam), but there is still pramād (negligence). - In this stage, all six leshyas are possible: - Krishna, Neel, Kapot (inauspicious) - Tejo, Padma, Shukla (auspicious) - So a monk in 6th gunasthana can be sanyami and yet have krishna / neel / kapot leshya.

1. 7th gunasthana – apramatta-samyat

- Here there is full sanyam without negligence. - In this stage, only the three shubha leshyas remain: - Tejo, Padma, Shukla - Therefore, a soul in 7th gunasthana cannot have krishna, neel or kapot leshya.

1. Tradition note (Digambar / Shwetambar)

- Both traditions accept this general mapping: - Up to 6th: inauspicious leshyas are still possible. - From 7th upward: only shubha leshyas, and later only shukla.

So, to your exact question:

• Can living beings with krishna, kapot, neel leshya be in sanyam?

– Yes, if they are in 6th gunasthana (pramatta-samyat).

• Can they be in 6th as well as in 7th (apramatta) gunasthana?

– They can be in 6th, but not in 7th; in 7th these three leshyas are no longer present.

For simple background on leshya and gunasthana you can read more here (leshya explanation) (gunasthana overview)