The initial DC9 model, the -10 series had JT8D-1 @ 14,000 lb thrust engines which could be operated at -5 ratings or 12,000 lbs thrust for increased life. The B737-100 and many -200 had essentially the same engine although I don't think they offered the derate so I don't know why the DC-9 couldn't have had a similar width cabin.
The -10 series had a hard wing with no slats. All subsequent DC9/MD80 models had L/E slats.
The hard wing models were especially sensitive to wing contamination. We did a "C" Check on a customer's DC9-14 and he requested at the last minute we polish the wing leading edges. My cleaners only got the left wing L/E done before a post check test hop. I watched the T/O, a full power one and being empty, he pulled it up pretty sharply after liftoff. The right wing dropped very suddenly and he was at about 45 degrees right bank. Nose went down and he recovered but came right back. It was difference between polished left L/E and unpolished right L/E. He got a partial stall on the dirty wing. Scared hell out of me and I was on the ground.
Re the Caravelles drag chute, never were used at New York. Don't remember the pax emergency oxygen system, it is now 50 years. The Suds didn't last long on that route fir which they were never designed for. They had very limited seating with huge legroom between rows as they were really stretching the range of the aircraft. Varig replaced them on the route with Conway powered B707-400 models.
I did get a rid in a Varig Caravelle though. They wanted to go pilot train but needed aft ballast for CG control. Instead of sandbags, they invited us and other airline workers to come along. My wife was picking me up at work that day and I talked her into going up for a "Jet Demonstration Ride", a real novelty at the time. Up we went and out to the East End of Long Island did approaches and go-arounds. No touch downs to save tires. When the cockpit door came open on one of the steep climbs she saw they had pillows stuffed over the windshields and almost fainted. Smooth, quiet and oh my, those big windows.