The fact that the post is actually structural should be determined by someone who knows i.e. Architect, structural engineer, reputable contractor. Same goes for the dormer (depending on what kind) Anything can be done, it’s only a mater of funds. I would not suggest doing this structural work yourself. Nor the electrical unless you are qualified. The least expensive thing to do is to get a reputable contractor (someone who’s work and dependability are verifiable by you from more that 2 sources and not people the contractor gives you as references). If this is not feasible call the local carpenter’s union hall. They will direct you to qualified and reputable contractors and carpenters. A final check would be your local building inspector. They will inspect the work of the contractor.