I am careful. In past posts I’ve referencd Pelagianism. I’m very aware of it. If you go back, you’ll see I have a consistent position (although I don’t repeat everything–it would take up pages and pages!) that two things are necessary: redemption by Jesus’s death on the cross and leading a good life (i.e., no mortal sins). Some people (not necessarily you) seem to restrict salvation to a certain group. This is simply not Catholic doctrine–Christ died for all people, Catholic, all religions, and yes, atheists. That’s a given. So could an atheist go to Heaven? Well, the door’s open.
As for your other comments, we agree. We don’t know who’s going to Heaven (except the Church certifies that saints are in Heaven). Only God knows. But I find it hard to believe that God would take an entire category of people (atheists, for example) and condemn them to Hell; they are individuals, and I’m sure each atheist has an individual story of why they are an atheist, etc. We may group them together, but that’s just for convenience.