Camera Raw Preset to PSD

Depends on the preset, but some of them are available  in the Camera Raw Filter along with the ones in the Profile Browser.

Meaning you can use some of the presets on an open image, not just camera raw files.

In photoshop Filter>Camera Raw Filter

Even if you could, it would produce vastly different results. The anatomy of an RGB file is very different from the anatomy of a raw file. To get the same visual result, all the values of the original preset would have to be recalculated, and separately for each color space (sRGB, Adobe RGB etc).

In other words, new RGB presets to emulate ACR presets. It wouldn't be worth it.

No, the settings/presets only work in Camera Raw and Lightroom.

You can open it in Photoshop via the camera raw editor (automatically) and then save the file as a Psd

This doesn't convert the original