Your explanation of the three tendencies is generally correct but it is dangerous and misleading to identify the first, the anti-imperialist one, with Shia Islam alone. Indeed there are plenty of non-Shia Muslims, such as the majority Sunni Syrians, who also belong to this category. Conversely, there are some groups, albeit small and fringe, who though nominally Shia have more in common with the Wahabbist tendency.

It is a mistake to attempt to make one-to-one correlations between religious denominations and political-ideological inclinations. The theological and doctrinal differences are more subtle than what this simplified picture would suggest, and frankly such religious debates do not concern us as Marxists.

We are interested in the real world political side. And the idea that Sunni and Shia Islam are irreconcilably politically at odds with each other is an invention of the imperialists that serves their divisive purposes.