It remains a mystery where the movie star lives.

[z7655431]

Can "it" (dummy subject) collocate with "wh-infinitives"? I know that "wh-clauses" can be moved to the end of a sentence by using "it" as a dummy subject.

For example:
Where the movie star lives remains a mystery.
--> It remains a mystery where the movie star lives.

What about "wh-infinitives"? (I know it's OK to just use infinitives)
1. Where to meet him is not decided yet.
1a. It is not decided yet where to meet him.

2. What to do tomorrow is still unknown.
2a. It is still unknown what to do tomorrow.

Are the two sentences (1a, 2a) natural and correct?

For me, they seem odd because I can only find "wh-infinitives" to be used as an object in structures like "ask, know...+ wh-infinitives". Why?

 

[emsr2d2]

1a is grammatical and I can just about imagine someone using it.
2a is technically grammatical but so unnatural that I can't imagine anyone using it.