the OP said nothing about using the MW
he also fridge for up to 8 hours
using His statement, i assume he wants to power the fridge while traveling
and the occasional overnight
also there are MSW that are designed for use with motors
like the tripp-lite PV1250 line
i think the best thing to do, would be look at specs and stated uses of the freedom 458
this is what the Xantrex site says
With filtered modified sine wave output, the Freedom 458 inverter/charger has the ability to run electrical equipment, appliances and even sensitive electronics. Perfect for any RV, the temperature controlled multistage charging ensures that your batteries are recharged quickly, and safety features such as automatic shut down protects your expensive deep-cycle batteries from excessive depletion.
this is NOT a cheap inexpensive inverter
i think the OP will be find
should not be any problems
like it has been posted he can test by running some other power tools or fans and check the motor temps
