I have to wonder about the sizing also. Depending on wall height I am guessing 14'-16' above ground? Typically it would probably come with a single skimmer and a single return. That filter appears to be an 80' DE filter which would take 40-80gpm flow and that pump, depending on the model, would deliver that. A lot of flow for those fittings to handle properly. Not working with DE a lot, I also have to wonder exactly how that particular filter would like going on and off all the time.
If I had to envision this system with a bigger pump I would like to see another return and a lower double (think safety) suction installed, positioned to offer better circulation. Most small standard pool pumps would be more than sufficient to operate this pool but efficient would mean low speed on a 2-speed pump. 3/4hp is about as small as they come I believe and so potentially 60-70gpm with a good pump and plumbing. 50' min cart. filter but 75 or even 100 for long filter cycles = less hassle. Sand might be minimum 24" but watch that hi-speed backwash flow or go 30" for real long cycles. All in all a huge overkill for a pool this size but man it would be clean! Run it on low speed a couple times a day for an hour or so and you will have plenty of turnovers. Hi-speed for chemical additions, hi use times, cleaning etc. You might even be able to backwash a 24" sand filter on low speed.