I find code inspectors to be very helpful if you approch them with hat in hand. In this case I would ask to come by his office to show them the sketch and get advice. Tell them you want to make their job easier by earning a green tag on first visit. Be prepared to tell them wherther you can move the soil stack nearer the W.C.
Code inspectors are spoke poorly of due mostly to people getting into contests about who knows best. The inspector ALWAYS wins,even if he's wrong. Do not argue,ask for permission and suggestions.