As others have pointed out, mosh doesn't support port forwarding, and because ssh doesn't support udp forwarding, can't easily be used with proxyjump servers.
Story time: I had tmux sessions active on all our servers and would simply ssh into my work laptop from home, so the sessions were never really closed. One day, I decided to upgrade from 1404 to 1604 and closed out all my sessions (including on the servers because I was pushing out a new tmux config). After 5 minutes we started getting smss that the system was down and couldn't write to disk. One of our production servers had been set up with an encrypted home folder and when my session closed out, it closed the encrypted folder. Unfortunately, the ssh folder wasn't outside the encrypted portion, so we had to use IPMI to restore access. That's the story about how we started joking that closing my laptop is a great way to break the production system.
Story time: I had tmux sessions active on all our servers and would simply ssh into my work laptop from home, so the sessions were never really closed. One day, I decided to upgrade from 1404 to 1604 and closed out all my sessions (including on the servers because I was pushing out a new tmux config). After 5 minutes we started getting smss that the system was down and couldn't write to disk. One of our production servers had been set up with an encrypted home folder and when my session closed out, it closed the encrypted folder. Unfortunately, the ssh folder wasn't outside the encrypted portion, so we had to use IPMI to restore access. That's the story about how we started joking that closing my laptop is a great way to break the production system.