Right, James, BUT - as you point out, the decision to put out Strawberry Fields and Penny Lane as singles was a record company decision, but NOT theirs. Also the planned order/sequence is different then planned - because back in the day- restricted ability of vinyl to hold the number of minutes the songs required dictated a change from their intended order.
As far as the "concept" of Pepper, yea it allowed certain constructive advantages and techniques, but this was very loose as a concept. The three songs omitted actually would have strengenethed the concept, as Only A Northern Song visits alienation/business/inner-life Beatle, Strawberry Fields is about childhood, literally, but figuretively about disassociation, perspective and mental journeys. Compare it with Lucy In the Sky - "Let Me Take You Down.....Picture yourself, on a boat, on a river..........
Penny Lane is also related strongly. Listen to Good Morning, Good Morning. Penny Lane describes childhood scenes, THEN, Good Morning describes those same scenes NOW....." taking a walk by the old school......"
If you get a chance, try integrating the songs into Pepper, then listen as a whole, really interesting!
"Step on the gas and wipe that tear away,
One sweet dream came true today!"