The way I see it. Religions are tools to be used. There is no such thing as a pure religion, the ruling class always co-opt religion to serve their purposes, and imperialist forces always co-opt religions to create conflicts. And when the working class become the ruling class, it will be no different, except that now it would be a tool to serve the common good.

Religious beliefs are to be inferior to laws, religious institutions are to be managed by socialist institutions. Beliefs, customs, and practices that no longer fit the new context are to be discouraged or even condemned. However, we must not rely on force to do so. The primary means are education and propaganda, consistent and persistent. The Chinese has a saying: 水滴石穿 (Water drips, stone wears away).

Disclamers:

I have only based my perspective on East Asian culture, which traditionally take it easy with religious stuffs. I do not know how different are the Islam societies.
The socialist government must be trusted by the people (having full legitimacy) in order to implement something like this.