All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
First of all, it should be noted that our website is not specialized in answering such misconceptions; rather it is specialized in giving religious rulings. Nonetheless, we have already answered these questions in Fataawa 83577, 83765 and 85108 with the exception of the question on the person who killed 99 persons. The scholars summarised the issue in the following three probabilities:
1) It might be that Allaah gave him a reward by which he would be able to recompense all the people he killed, and he would have enough reward left for him to enter paradise and be saved from Hellfire.
2) Allaah Himself will recompense the people who were killed, out of His Mercy and Favours.
3) The killer might have killed these people deeming killing as a lawful act, and thus he went out of the fold of Islam, but when he repented from his disbelief, all his previous sins were forgiven. Allaah Says (what means): {Say to those who have disbelieved [that] if they cease, what has previously occurred will be forgiven for them.}[Quran 8:38].
Finally, we advise you, dear brother, to preserve your religion from such misconceptions and not listen to them [misconceptions], as they might find a way to your heart and you will not be able to repel them because of your weak faith or lack of knowledge or because of both. Indeed the scholars stated that it is forbidden to read the books of the people of the book as they are forged and falsified, let alone listening to their misconceptions about Islam.
Allaah Knows best.