The previous idea probably won't work. You can create multiple instances of the same set of Application Properties, in PM click on the Profile then the + and you can create another Instance.
Then in your WF in the Project settings there is the Application Properties tab, on the Profile Name the "Selected Instance" has a dropdown where you can select which Instance, and it will list all you have created.
I'm unsure of how to dynamically change this, there is an option for Project Property, not sure where that gets set.
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You could create a custom Table using the Integration Components DBDT which stores all these values and have multiple rows, then decide which row to use at runtime.
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Scheduler: You could create a vbs script that calls your published workflow and set the schedule for each one you want.