Not having a save before you built the house was a mistake. The workbenches are only a temporary thing, not something that should be left in the house after you finish furnishing, especially not Lakeview. Removing all workbecnhes could solve the problem.
The other glitch was with the Greenhouse wing, but if you have that one your only option would be to delete Hearthfire, lose everything in the house and all the materials you put into building it and start again. There are plenty of threads on the subject, most you would find in the support sections for Hearthfire.
http://www.gamesas.com/forum/205-xbox-360-hardware-and-software-support/
There are several problems that can arise depending on how you built the house, these could also contribute to problems later, you can only get rid of them by going back to a previous save and rebuilding the house again. Deleting the DLC and saving so you can start again is not only going to lose things, but could also introduce more glitches later. But if you have no other options, that is all that is left if you want that character to have Lakeview Manor.