What is required of one who stopped praying for ten years and did not pay zakat during this period, while continuing to fast? Is he required to make up the missed prayers and zakat?

If the ترك of prayer and zakat is due to laziness and not denial, then the missed prayers must be made up and past zakat payments must be rendered, because zakat is a right that does not lapse with time. However, if the ترك of them is due to denial of their obligation, then this is an act of disbelief that expels one from the fold of Islam. If the person returns to Islam after disbelief, they are not required to make up the prayers and zakat payments that were missed during their time of disbelief. But if an apostate returns to Islam, they are still liable for the zakat that became due upon them before their apostasy. As for zakat during the period of apostasy, the well-known opinion is that their ownership is suspended; if they return to Islam, zakat becomes obligatory, otherwise it does not.