Rebex Secure Mail supports AES-128/AES-192/AES-256 in CBC mode.
Full support for RSAES-OEAP (RSA encryption with OAEP) and RSASSA-PSS (RSA signatures with PSS) has been added in Rebex Secure Mail 2017 R6.
Rebex SFTP transport layer is SSH protocol, and our implementation does support AES-128/AES-192 in CBC mode. However, RFC 3565 nd 4056 are not relevant for SSH - they extend Cryptographic Message Syntax (CMS), which is the core of S/MIME, but not of SSH. RSAES-OAEP in SSH is not supported either - RFC 4432 defines the appropriate key exchange cipher based on this, but it's seldom used (unlike classic or elliptic curve Diffie-Hellman which is ubiquitous) and not supported by Rebex SSH at the moment. Sorry!