Can I undelete a question I deleted on meta SE? If I can will I be able to get back all answers and comments on that question?
This is just like on the main page. That is, if you deleted it by yourself, then, yes, you can typically undelete it and answers and comments will be restored, too (except of course if they were deleted separately).
An issue can be to find the question again. This can be tricky when you do not have a link stored. But if it is somewhat recent then you can find it in your question page via following the link at the bottom to "deleted recent questions." (The same is true for answers, and attached comments, if the question is not deleted.)