There's no stoning in the Quran, it's from some idiotic Hadith, if it was an important aspect of Islam, Allah would have put it in the QuranWhat is neo-sharia? If you do not believe in sharia, you are a kaffir.
Also, if you don't believe in amputating the hand of the thief you are kaffir and if you don't believe in stoning then I think this is kufr as well.