Novus 2 is a very mild abrasive, but it's made for plastic. I've tried several different metal polishes and now only use Blue Magic polish. They claim it leaves a protective microscopic silicone film after polishing, which you can easily feel. Makes metal parts shiny and very slippery. Great for stainless lane guides and any part the pinball touches. I cringe when I read people saying they've used car wax on metal ramps and other parts. Polish it right the first time and you won't need car wax on your metal parts.
The only place I'll use any oil, synthetic or otherwise, is on spinner axles. I rarely use dry lube, but have used it occasionally. Would never put any oil on a plunger, but I can't fix EM's, so I'll just wish you good luck.