Generally and specifically for this lineup a dual screens and mimic Mr. Mime would be more useful; mimic generally being there to abuse certain moves & field effects.
Musharna's purpose at this point would be to put things to sleep, which if combined with Moonlight and Psychic could prove useful, but moreso if you plan on using mons like Sawk later on, as the sleep will allow them to set up (Bulk Up, etc.).