would a moonstone cart be compatible with a sony ps-x7 turntable and scott receiver?

The Moonstone has a compliance of 12, so I would think it should work with a variety of arms, including your Sony.....I would think.....My guess is it should work fine. Whether your receiver’s phono stage will get the most out of it may be another question. But it should ‘work’, regardless.

No, not personally, but it has had some glowing reviews. Michael Fremer being one. I considered it recently as a back-up cart, but eventually went with the Goldring 1042 for that duty instead.