They are mostly correct. Most of these sentences are missing the words �the � or �of �.
My birthday is the 4th of October.
My birthday is on the 4th of October.
My birthday is the 4th of October.
(This sentence becomes the same as the first. OR you could say "My birthday is October 4th.")
What day is the 4th of October?
What day is the 4th of October on?
What day is on the 4th October?
What day is October 4th?
(What day is 4th October?)