Updating plugins with no FTP

Hi All

It might look as a beginners question but read it all before you judge it.

I have a server that accepts SFTP (SSH) but no FTP or FTPS. I can update most of the plugins by uploading manually to the server directly instead of using the updates. I am running into 2 issues:

1. MU plugins uploaded to the MU plugin directory do not appear on the plugins list to be activated or deactivated
2. I need to find a workaround so i can set my non-technical administrator to update plugins by himself

1. are the connections outbound (server connects to another server to download) or inbound (server sends the connection information for some server to connect and upload)?
2. Any way to update without FTP/SFTP
3. Any way to update with SFTP?
4. Suggestions?