Umberto Eco is a smart guy but that essay is pretty silly. Fascism: anywhere, everywhere, and you can tell it's coming by any number of contradictory and non-definite phenomena.
If I were to try to grasp fascism from a different angle and how it relates to other totalitarian tendencies I would characterize it by the social class that puts it into power. The middle class has been the historical base of power for fascism. The points Eco makes are quite resonant amongst middle class people in many countries in particular the downwardly mobile middle class who feel like they are being cheated out of something they are entitled to. That is the mechanism by which fascism takes hold.
In contrast, Marxism-Leninism is primarily concerned with the proletariat and intelligentsia. Maoism is primarily concerned with the peasantry. Really, you can identify a political ideology without looking too closely at its details by examining how it goes about class struggle: its implementation as an actual political movement and not an abstract set of ideas.
I find the "social class" analysis just as unsatisfactory. You might usefully characterze these different tendencies by their rhetoric, but if you insist on looking at them as an "actual implementation", I tend to find that they're just the same side of the same coin - a small state political class enormously empowered, and all other "classes" being simply categories measuring the loyalty and proximity to the state class.
Sure, he's describing major features of the category of political thinking that he calls fascism - but with the purpose of seeing it coming and doing something about it. He says: "Ur-Fascism can come back under the most innocent of disguises. Our duty is to uncover it and to point our finger at any of its new instances—every day, in every part of the world." His article is a rubric for identifying its features. Yet to say that fascism may have any of the enumerated features, in almost any combination, with drastically varying applications and manifestations, is to construct a category so broad that it is practically useless. It's a recipe for calling, and perceiving, almost everything as being nascently fascistic. We need to make better distinctions than this, I feel.