Yes you can pay for a set of plans and for each “segment” you elect to permit and every change those “segments” cause as they affect each other.

You’ll be far better off to develop a final plan and permit the whole thing and work the inspection system to prolong the project.

You don’t need an expensive architect to do this. I once worked for a draftsman who did this very thing, but did not have the expensive schooling and licensure of an architect. You may want to look up companies in the design and drafting business. They will do what you said and obtain permits for the work if necessary. They probably also have networked with builders to give you a good price for doing some of the work, just as my former boss did. You only want someone who is experienced, though, who understands the importance and details of maintaining your house’s structural integrity.

It’s called an achitect.