First I would like to clarify my words a bit,

I apologize for that! Now that I read you again, yes your wording was pretty clear, I misunderstood. As you can see by my poor expression, English is not my mother tongue, and I often misunderstand some nuances like that. Sorry again!

the concept of “invincible ignorance”. and from what I’m searching the “inculpable ignorant” in Islam. basically applies to people who have never been exposed to the religion

No it's still apply. I'm not Catholic myself, but I'll use again Catholic texts, as they are a very hierarchical denomination it's easier as they have authoritative texts. In Gaudium et Spes, a document from the last council (so one of the most authoritative texts of this church), it is written:

taken as a whole, atheism is not a spontaneous development but stems from a variety of causes, including a critical reaction against religious beliefs, and in some places against the Christian religion in particular. Hence believers can have more than a little to do with the birth of atheism. To the extent that they neglect their own training in the faith, or teach erroneous doctrine, or are deficient in their religious, moral or social life, they must be said to conceal rather than reveal the authentic face of God and religion (§19)

One can then be atheist not because they never heard of Christianity, but because the Christians themselves taught by their words or their acts something wrong about the Church. And I mean, I'm a Christian, and I can't reproach people to hate the Church (and by Church here I mean the Christian one, not specifically the Catholic one) when I see how far from the Gospel it often is! I didn't heard what Francis said about atheism, so I have no opinion on the matter.

For Islam, as it's a more horizontal faith, it will be harder to find clear proofs, but from discussions I had with Muslims I know, it's more or less the same thing. They said to me that Islam is badly spoken about in our Western society, so even if they know what Islam is and have mosques around them, they still are seen as ignorant.

Eskimo: “Why did you tell me then?”

That's a fun story, I never heard it, thanks!

If I were this missionary, I’d answer something like this: outside evangelicalism again, the Christian faith is only secondarily about salvation. If you read the Gospels, for example, Jesus almost never speaks about the afterlife. And when he does, he generally isn’t actually teaching about the afterlife; rather, he uses it as a metaphor to teach us how to live a full life here and now. The same is true of the Old Testament.

Paul emphasizes the subject more, but his point is something like: "This question is settled: you are saved by grace, so stop worrying about it and do good instead!" The problem is that his definition of “doing good” comes from a man living 2000 years ago, and some people (within evangelicalism, but unfortunately not only there this time) nowadays focus on the details of his definition of a good life rather than on the spirit of his teaching.