SharePlex replication should not be affected if using Oracle Network Encryption.
If SharePlex connects thru sql*net, then Oracle Network Encryption kicks in (if it is configured) but it will be transparent to SharePlex.
If SharePlex connects thru bequeath, then the encryption does not come into play.
The Oracle Network Encryption has no bearing on the configuration of SharePlex’s AES encryption in the sense that they do not interfere with each other.