Brother,
I can't imagine that the parents of prophet s.a.w can be in hell.
But when even this issue is disputed among scholars then how you can confirm of people of makka as people of heaven without any evidence.
As far as people of fitrah are concerned they might be among believers provided that they followed the religion of any past prophet and didn't commit shirk.
But after the advent of prophethood it's not applied to those who are unaware of Islam as we've no evidence of them being exempted from hellfire.
Its good that you cant believe it because that means that you still have the ability for sound reasoning and logic ... even general remorse as well as love for the Prophet Muhammad (PBUH).
I never claimed that the people of makka are people of heaven. I am only suggesting that they will have a different judgement/judging PROCESS than you and i. Becuase they didnt get a chance to hear about islam like you and i did. And thats why their condition is different and should have a different judging process. Like wise the infant or mentally handy cap person will be judged with a different process than us. Because their conditions were different! Unlike us were we are presented with the true islam, given the ability to comprehend that message and given the ability to accept it or not!
Think of it like this. A robot designer designs 1000 different types of robots. Each with different levels of intelligence, capabilities, tools, specs and what not. The designer decides to make a test for them and see which one will complete the test ... those who fail are considered unworthy of keeping and those who pass will get to stay. The test was done and finished.
Some of these robots had all that it took to pass this test and more but didnt try hard enough or were too arrogant.
Others barely made it.
Others didnt have what it takes to complete one part of the test and resulted in them not being able to continue with the rest of the test and ended up failing
Others were not even informed about the test and never attended it.
Now tell me, is it fair for the design to decommission all those who didnt pass as punishment, even though the designer was the one who made them that way and causes all their mishaps? Ofc not!
That is why these robots should be given another test to see if they will be worthy of keeping or for decommissioning.
Similarly, the humans who didnt get a chance to know about islam correctly will be given a second chance to prove themselves infront of god. I am not suggesting that they will automatically go to heaven! there is a difference between being given a second chance and being given paradise without proof of their worthiness.
Lastly. You are still thinking through a black or white mentality. No brother, even after islam came, some people will still not have heard of islam like the people in North Korea (Even the internet itself is illegal over there) and isolated tribes in africa. Allah will not judge them like he will judge us. He will give them a different trial completely. Again ... i am not suggesting they will go to heaven, i am saying that they will be given another test to assess their imaan. If you think that Allah will not do this then by definition, your version of Allah is an unjust God and i do not believe in that, Because i believe in what Allah said about himself in (Quran 8:51)
... and Allah is not ever unjust to His servants.
As for the Prophets parents, they will must be even a second chance as well ... whether they will pass this test or fail is a completely different story. So im not suggesting that the scholars and hadith is wrong, just that they will be given a second chance at proving themselves to Allah AWJ. Hope things are clear now and you understand what i was trying to say.