1) All of them. Although sometimes they are stable (non-radioactive) daughter isotopes.

2)Many can, sometimes several daughter generations are created before you finally get a stable nucleus.

3) Sometimes several, although it is always a finite number.

4)Many, although if they are stable, there is no way to determine they are daughter nuclei.

5) No. Although ionizing radiation can effect the electron shells of atoms, it is not energetic enough to affect the nucleus of another atom. However, ionizing radiation is released when a radioactive nucleus disintegrates.

I used to work with a material called a "radioactive cow". It was a very long-lived, insoluble radio-isotope that produced a daughter nuclei, which was highly radio-active with a very short half-life. The daughter element was soluble, so pouring a liquid through the cow released a solution which was highly radioactive, but only for a few minutes (its daughters were stable). It was then possible to safely work with a highly active species, because it quickly became inert.

Any radioactive sample contains unstable atoms exploding at a certain rate, plus daughters, some of which may be radioactive themselves, plus stable atoms which are the end results of these radioactive decays. The measured radiation from the sample includes its own radiation, plus the radiation from it's daughters. Some of these daughters are other isotopes, which cannot be chemically removed from the sample, but some are other elements, which can be removed by chemical means. The proportions of non-stable nuclei in the sample quickly reaches equilibrium, but the stable daughters steadily increase in number.

I can see where you are taking this, Johannes, and we are not letting you get away with it. This process is perfectly natural and it has been going on around us all since the nucleogenesis first occurred in the cores of stars soon after the Big Bang. It is not the cause of global warming.