Dual-Stack Lite is a NAT solution. Active mode requires, that the client is directly reachable by the server (e.g. no address translation in between), so it will not work if the client is behind any kind of NAT. Passive mode requires that the server is directly reachable by the client and thus does not work if the server is behind NAT.
Worse, if both sides are behind NAT FTP will not work at all, unless these NAT solutions include helpers which rewrite FTP traffic. A workaround would be to use a protocol which does not use any dynamic ports (like ssh/scp/sftp) or have a VPN between the local and the FTP servers network so that they can reach each other without NAT.
Simple port forwarding might work if you can restrict the range of allocated ports used by the client (active mode) or server (passive mode) and have port forwarding established for the complete range. Additionally client (active mode) or server (passive mode) must not send there own IP address inside the PORT command or response to PASV, but the public IP address visible by the peer. If and how all these can be configured at client/server side depends on the specific client/server.