Wonderful, well..first with apostasy, it's what mainstream shiekhs have concluded, while in many verses in quran allah give you the to believe in him or not, he even addresses prophet mohammad saying do you think you can force people to be believers? , he says also in many verses addressing the prophet that you are only a messanger who delivers a message and that's it, the messenger wasnt asked to make sure of applying sharia or islam upon other, alalh gave him his role which was only delivering the message of allah.

As for stonning, well..to start with; mainstrwam shiekhs say that adultry are punished also by stoning to death if he or she was married, and wipped if they're not, and this they brought from stories that were told about the prophet that many suspect they happen, while allah in quran says the punishment is wipping no matter who if they were married or not.

Now for homosexuals, who told you that their punishment is stonning to dearh, they concluded this from the punishment of people of the prophet Loot, who were all committing this sin among many other sins, they used to assult on conveys passing by their lands and they abused each other in many ways, so they concluded this from the story of those people. While allah different punishment in case both were males ( the punishment is to harm them by talk only) and females ( the punishment is to hold them in homes). Why he assigned punishment? He assigned punishment not for homoshexuals, but alos people who commits adultry.