That sounds like the sort of fascist puppet states all over German-occupied Europe. It would have its supporters, but would be hated and resisted by many. That's not a good recipe for a fascist state, which needs a more organic organisation and establishment to be successful.
The hypothetical anticolonialist sort of fascism would be as good for Ethiopia as it would anywhere else (so a mixed bunch at best, like the anticolonial sort of socialism has proven to be), and likely better than the Italian-imposed fascism, but the big problem is that the biggest threat to Ethiopia is a fascist nation, so almost by default Ethiopia must be antifascist. You'd need Mussolini to be dead-set against any further expansion of the Italian colonial empire except at the expense of other colonial empires, yet also big into preaching anti-imperialism (hey, Imperial Japan did it), with regular condemnations of Anglo-French imperialism ("clearly, Italian colonialism in Tunisia would be much more benevolent than the brutal rule of the French!").