I have an FXPak Pro & I can confirm that Lil Manster does work on real hardware.
Is the ROM file broken? Are you using the correct ROM? Is the Everdrive powerful enough to run Lil Manster? There's honestly a wide variety of reasons why it may not be working on your end.
Out of all the English FE5 translations, this one has the highest potential of being fully translated. Even if progress is coming along slowly. Keep up the good work!
BTW, found a spelling error.