If USCIS actually processes these applications, I think that it's a great rule but the Administration has made it clear that it doesn't like the rule and will try to do away with it.

Is it correct that the entrepreneur rule was reinstated by court order (https://www.uscis.gov/news/news-releases/uscis-begin-accepti...) so that entrepreneurs could actually file for this right now? (until they undo it)

In case they undo the rule, would the already issued paroles and EAD cards be void?

That's right but given the open hostility to the rule, I don't think that these applications will be processed to completion.

I've spoken with parties highly involved with the IER that are actually much more optimistic. Would recommend everyone talk to their immigration attorneys about their own status and whether applying is worth it or not.