You need to get a copy of Hubbard’s Compiled Military Service Records. It will cost you money. I believe this website offers copies of the CMSRs as a means of supporting the expense of operating the website. Otherwise, you can go to the National Archives website at http://www.archives.gov/research/military/civil-war/resources.html and order these records.
Well meaning family historians and other interested researchers usually manage to get things garbled and you will end up wasting your time chasing your tail trying to unravel their misconceptions about Hubbard’s service experiences. For example, I’ll bet you that “Trevillian Station” and “Civilian Station” represent one capture and imprisonment episode in Hubbard’s life!
Depending on his health when released from imprisonment, Hubbard would have been taken first to the hospitals at Hilton Head, South Carolina for examination after his delivery at Venus Point. From there, he may have gone to Parole Camp in Annapolis, Maryland and from there sent back home to Michigan to the place where he first enrolled.
Once you have his CMSRs, the answers to many of these questions will become clear.