The order of the "drains" is completely irrelevant. NO ONE arranges their sinks, toilets, and tubs so that they connect in some order, nor do we route the plumbing to make it happen that way. The shower being 5' from the lav is also meaningless, unless the piping is installed to take advantage of that someway. IT is like saying your table is 5' away from the refrigerator but the milk bottle on the table still spoils. EVERYTHING depends on HOW you install the piping, NOT were they are located.