You can’t in good conscience let a young child watch Gremlins. A man has his arm ripped off by Gremlins. Halfway through the movie, a main character describes the grizzly, comic death of her father. Gremlins is too scary and too violent, if only by the slightest margin.
On the other hand, you can definitely sell a Gremlin’s lunchbox, trapper keeper, stickers, etc to a young child. This is kind of the point of Gremlins: it is a movie designed to be snuck into. The movie is a dare.