The AfD candidates were in their late-50s to late 70s, some apparently with serious preexisting conditions, all ruled natural deaths (and one suicide). I have no idea how to substantially proof the absence of a conspiracy but I see no evidence to the contrary. I would, however, be extremly interested in seeing the math from the people claiming this to be "statistically extremely unlikely". It lacked rigor in the past. The thing with unlikely events is, that they tend to happen if your sample size is large enough. :D

Nitpick: Second most popular (looking at the federal elections from this year). And I think they have no realistic chance to govern any time soon, as no one from the other parties (the other 75% of the vote!) wants to form a government with them. There is this joke, about the left splitting their vote share over too many small splinter parties: The biggest enemy of a rightist (?) is the leftist - the biggest enemy of the leftist is another leftist who holds 98% of the same beliefs!

I am confident, that I could call our current chancellor every insult under the sun and not be prosecuted for it. (I am aware of the incident with Andy Grote, which has since been ruled unlawful and unreasonable. I would assess this more as a case of improper use of influence / corruption than systemic prosecution). Conversly, were I to call for his murder, I think prosecution would very much be reasonable. Escalation to violence has, in my opionion, no place in the political process. You are welcome to disagree.

I (honestly!) hope your institutions are up to the task of defending that first amendment. I increasingly get the feeling, that a constitution is of little use, if no one in power is willing to stand up for it.