iPad Pro 12.9 inch

go here

iPad Pro 12.9-inch (4th generation) - Keyboards - iPad Accessories - Apple

in the menu to the left you can click on the various 12.9 ipad pro models to have it only show the keyboards of the model you own

See this:--> Identify your iPad model - Apple Support

Then take a look at this list:

Here is Apple’s definitive compatibility list for Apple Pencil and iPad:

Apple Pencil compatibility - Apple Support

iPad Pro models with a physical Home button and TouchID are not compatible with the second generation Apple Pencil - but can be used with a first generation Pencil.

iPad Pro models with FaceID support the second generation Pencil.

No.

If it is an iPad Pro 12.9" 1st generation, it supports Apple Pencil 1st generation only.

As far as keyboard is concerned, see this page:--> Keyboards - iPad Accessories - Apple

Regards

Giulio