I was listening to Ml. Ilyas Ghuman DB on his lecture on the Mamatis (which includes Wahhabis). He said it is not permissible to pray behind them. How could we justify praying behind Wahhabi imams from Saudi? Many Wahhabi imams have visited Deobandi madaaris and led salah there. How do we justify this? Is it because we do not know the explicit beliefs of these Wahhabi imams?
As for his reasoning, it was follows:
The Qur'an says that the shuhada are alive - in both body and spirit. It then means that the Prophets and Rasoolullah are also alive - in both body and spirit. The Wahhabis ask how is this possible because Rasoolullah did not talk about the anbiya عليهم السلام nor does the Qur'an do so when it talks about being physically alive. The reasoning that Ml. Ilyas used was very complex (it was a 2 hour lecture). An example to make it easier to understand is that there is no mention of 27 times reward for the imam of a jamaat. Does that mean the imam does not get the reward? Also, when asked about Ihsan by Jibril , Rasoolullah mentioned that it is to worship Allah as if you see Him and if one is not at that level, then it is to worship Him as if He sees you. Does that mean that that those who are of a higher level are not conscious of the fact that Allah sees them? Of course not. So, the logic follows that the lower is included in the higher so the reward of the shuhada, which is actually earned by following the steps of the anbiya , is also included in the reward for the anbiya عليهم السلام.
He also talked about the difference between يشعرون and يعلمون, where one refers to physical evidence that can be sensed and the other refers to belief. So, if Mamatis say that even the shuhada are not alive in the physical sense (and Mamatis and Wahhabis do say this), they are lying or are ignorant because the Qur'an says that they are still alive but not to our senses. So, even if we cannot sense life in them, we still must believe.
And then he says to reject such a thing is rejecting the Qur'an. He made a point not to use the ahadeeth as reference, even responding to a Mamati question in the question/answer period when someone mentioned that a hadeeth used by Hayatis/Ahlus Sunnah is "ahad" and "ahad" narrations cannot be used as proof (it was really funny to see such a question when no hadeeth was provided as evidence and Ml. Ilyas responded that does the questioner believe the Qur'an to be "ahad" as well). So, essentially, Mamatis reject the Qur'an.