Yes, in some contexts.
No, under most circumstances.
Undecided - you tell me!
I am interested from teachers whether they would accept...
Everyone is strong who is healthy.
If yes, are there any conditions that might make you not accept it (ie contextual factors or a different noun quantifier).
Would you also accept...?
The man is strong who is healthy
If no, are there any conditions that you might accept an extraposed relative clause.
This structure is a little uncomfortable for me but is used extensively in logic exercises.