If you live in the city limits and permits are needed, you will need an architect to draw plans to be approved for permits.
Usually, out of city limits, a contractor may be able to do it.

I drew my own plans, while out of city limits, and a contractor did the job.
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I may be biased but I think that the complexity of what your trying to do would justify using an architect. Architects will be able to help you achieve a quality design that you’ll be proud of while adhering to local codes and zoning regulations. You may have some structural challenges that they can help you with as well.
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Architect

I would say yes, because you will have a nice plan and you can price it out effectively to subcontractors and compare apples to apples. Also adding the garage will require lam beams or steel so they have to be sized by a licensed AIA. Contractor cannot do this , even if he is able, because it will need to be sealed. Or if you are submitting the plans owner builder then the Contractor can do it if you feel confident in his ability. I would say its safer to have the AIA look it over. After you get a plan draw you can price it out better. And see it better for yourself. good luck
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builder