Well, there must be something - if only because those are all things that happened, and that we recognize as meaningful in a general context.

History is obviously (and fairly) biased towards things that happen, and since we can't build much of a historical analysis around things that didn't happen, we are bound to attempt interpretations, seek explanations and build narratives around the main, most recognizable moments occurring in what we then term "history".

This means that we are fundamentally bound to identify a "path" linking those moments together - how strong of a connection depending not only on the matter itself, but also on the character, scope and origins we ascribe to the "historical process". The idea that you hint at in your question - that of Germany (and to a lesser degree Italy) following a "special path", compared to nations oriented towards forms more open, albeit not exclusively, to democratic liberalism, is indeed generally referred to as Sonderweg (which is just the German expression for special path, a course of its own), and I'd rather not discuss it because I am certainly not a specialist on German historiography of the XX Century.

I'll content myself with pointing out that such threads connecting "historical moments" are almost intrinsic to a historical formulation - they do, after all, follow from our own individual approach to the events of our lives - but that in recent years, once the paradygm of "western" progress had come into question, interpretations of other "national" histories relying on departures from the "western" model embodied by France and Britain as explanatory tools have certainly lost popularity. Similarly, there is an increased tendency to stressing the impact of "contingency" in the historical process, and of building narratives compared to recording them; which means that the presence of a strong, causational link between Germany's national history and the affirmation of the National Socialist political project (the path "from Luther to Hitler") is seen as increasingly dubious.

I'll do my best to illustrate a few examples and limitations of this "path-building/path-finding" in relation to the case of Italian Fascism.

For one, you correctly pointed out that both Germany and Italy completed their unification much later than France and Great Britain (but not really that much later, for instance, of the United States). What casual observers often miss is how deeply aware the Italian national leadership and political and economical establishment were of this belated unification and of its supposedly dramatic consequences in relation to Italy's ability to compete and participate to the great challenges of western civilization - whether Italy could, eventually, step up to the level of France and Britain, and not merely and exclusively in an expansionist and imperialistic sense, but also in terms of nation-building and identity-shaping. The obvious tendency to interpret signs of a relative economical stagnation, or manifestations of social conflict as consequences of that original, fundamental flaw - that laggard unification, which left the Italians themselves "undone" - meant that, when Germany arose as a great European power soon after its own unification, a portion of the Italian leadership begun to look at the more authoritarian, organic structures of the German State as a viable alternative model to liberal-western development.

Here we run into a first issue requiring some nuance to sort it out. Because the objective elements of "underdevelopment" - some of which could not be remedied objectively (Italy didn't have the same access to coal of Britain and Germany, nor the ability to consolidate a commercial navy position able to prevent the threat of British economic pressure) - were enhanced by their general perception as factors of instability. It is both to answer those objective limitations and their perception that Italy felt called to find a way - perhaps a special one - into modernity.

The idea that this struggle was one of the fundamental - if not the essential - cause of Fascism, is at the root of A.J. Gregor's quite dated (and mostly regarded as dubious) interpretation of Italian Fascism as a "developmental" authoritarian form (here Gregor obviously drove impulse from contemporary examples during the 1960s and 1970s); that is a specific form arising from the need, structural or perceived, to address the challenges of a belated industrialization/modernization.

As you can see, at this point the analogy between Italy and Germany beguns to become shaky, as - unlike Italy - very few would have argued in 1913 that Germany was a nation struggling to modernize. Indeed its path from belated unification to industrial and cultural modernization was anything but lackluster. There, the narrative of German defeat and subsequent crisis is in some way appears, and was framed at the time, as a narrative of contingency rather than necessity - Germany was strong enough to be victorious, yet it fell, and the search for such an explanation (later taking the mythical form of the two-headed foe of Jewishness-Bolshevism in Nazi propaganda) as well as the need to come to terms with the defeat added a further layer to the perceived social and political crisis of Weimar Germany.

Meanwhile, in Italy - a victorious nation (and to some the Italian victory appeared as shocking and unexpectedly after three and a half tears of war as the German defeat had come to them) - Fascism had already appeared and taken power quite rapidly. There the "enemies of the Nation" could be accused of sabotaging the war effort only to a certain extent, as the Nation had been, after all, victorious despite their best efforts. Yet the establishment had "squandered" the spoils of war conquered on the battlefield in a display of political inadequacy and diplomatic incompetence. The narrative of a victorious Nation - gaining "the greatest victory ever won by an army ever" and shattering the once almighty ruler of half Italy - being deprived of its rightful claims due to the ineptitude of its political leadership, in turn a leadership expression of a pale imitation of French and British parliamentarism, is neither particularly accurate nor universal enough to be taken at face value, but appeared as a substantial enough part of public discourse (and remained in the Fascist narrative thereof) to create a lasting legacy as a reasonable and accessible explanation of Fascism.

If the Germans were angry, resentful and desperate because of defeat, reparations and economical crisis; the Italians must have been angry, resentful and desperate as well, because... of the Mutilated Victory. What matters here is that this is a narrative of necessity - of inevitability even - Victory itself could not deliver Italy from its incompetent leadership and backward social structures: the Nation which had found itself on the battlefield deserved a ruling class befitting it, a leadership expression of the new "aristocracy of the trenches", not a government of military men, but a government of the "combatants" and of the "producers". Only thus could Italy hope to pick up the pace and enter the great international competition - that the nationalists, and Fascists as well, continued to envision in the form of an ultimately irreducible conflict - on equal grounds with the Great Powers.

Italy's position as "the least of the Great Powers" is another traditional element for interpreting the rise and affirmation of Fascism (from Albrecht-Carrie to Bosworth). But it certainly doesn't work as well for Germany: there you have militarism instead. And German society - cultural and social developments aside - was indeed regarded as somewhat unbalanced, due to the extreme importance ascribed not only to the military itself but to the idea of militarization.

In this sense Italian Fascism appears to fit with its need for societal mobilization and "organicist" approaches to education leading to a proliferation of militias and youth organizations; but this by and large wasn't true before the rise of Fascism, when the Italian military had neither the reputation, nor the effectiveness, nor the social stature of the German one. Indeed a profound disconnect existed between military and society, with the army being regarded by many - up until the Great War at least - as little more than a, costly, glorified militia, dedicated for the most part to ensuring public order. A transformation - a motion in the direction of what Mosse termed the "nationalization of the masses" - appeared to take place just before the rise of Fascism, with the development of a cult of the fallen during the peak of social conflict in 1920-21, but not really to the degree and with the depth this process had taken place in other European nations.