To answer the question in the thread title, to find pro-Hitler Liberals you need to look at the Liberal politicians of the '20s and '30s. After all, Mussolini and Hitler just took just took Liberal goals and positions and cranked them up to 11.
As for a definition of fascism, I like Jonah Goldberg's: "Fascism is a religion of the state. it assumes the organic unity of the body politic and longs for a national leader attuned to the will of the people. It is
totalitarian in that it views everything as political and holds that any action by the state is justified to achieve the common good. It takes responsibility for all aspects of life, including our health and well-being, and seeks to impose uniformity of thought and action, whether by force or through regulation and social pressure. Everything, including the economy and religion, must be aligned with its objectives. Any rival identity is part of the 'problem' and therefore defined as the enemy."
Mussolini started his political involvement as a socialist, but was unceremoniously kicked out of the Italian socialist party for his support of WWI.
Note that the reason he was expelled had nothing to do with his
economic views but his rejection of
internationalism. That is one of the major differentiations between communism and fascism, nationalism vs. internationalism.
Capitalism isn't about state or private control but about private ownership of capitol assets.
The
Merriam-Webster definition of capitalism: "an economic system characterized by private or corporate ownership of capital goods, by investments that are determined by private decision, and by prices, production, and the distribution of goods that are determined mainly by competition in a free market."
I don't see anything in that definition that includes massive levels of government regulation of the economy, such as you find under fascism/nazism or communism.