yeah, The One is the anomaly brought forth by the Third Matrix, the one seen in the movies.

Seraph Cannot be another One as he was from the first matrix, well before the anomalies advent

Neither can the Merovingian, as he was from the Second, more horrific Matrix.

Also keep in mind of the six cycles, they freed themselves and the chosen to create Zion.

Occording to Morpheus, the previous One had died (reasons not known), It's safe to say that the others had died in the same fashion.

Neo is the only one to deviate from the rules, and made sure that there was no need for another One.

There are no Ones alive