You seriously think non Catholics can be saved with invisible ignorance as a possibility??????
As St. Thomas would say ... aaah,
distinguo ...
I believe that invincible ignorance combined with lack of actual sin could prevent eternal punishment, but that it's not the same thing as "salvation", which entails the Beatific Vision, and only the baptized can receive that.
Now, very little has been made since the BoD era regarding the character of the Sacrament of Baptism, where it's been reduced to some non-repeatability marker, perhaps a badge of honor that some in heaven have and others don't. That's nonsense. If someone wanted to say that an angel would come to baptize people who are to be saved, or something along those lines, I'd find that much less satisfactory.
So we know that by our NATURE we are incapable of the Beatific Vision, of seeing God as He is. We have natural faculties, but lack the supernatural ones by nature. So this character of Baptism is what endows us with the supernatural faculty or capability to see God. It's also marks us, similar to giving us the DNA of Christ's Body, where we are recognized as God's sons ... albeit by adoption ... and therefore members of the family of the Holy Trinity, in the Kingdom. God sees His Son in those who have this character ... of His Son in them. Church Fathers referred to this seal as the illumination or enlightenment.
At the same time, those who are invincibly ignorant and practice natural virute, etc. ... I believe they can attain to a certain level of happiness, or at least certain degress of non-suffering in eternity. Are they saved? No. Are they in Hell? Well, depends on how you define Hell. I think that there are almost infinite "levels" of happiness/punishment depending on your practice of natural virtue or vice, but election to being elevated to that supernatural state, which is owed to no one, can only be possible through the Sacrament and the character it bestows.
I believe that's what Father Feeney was hinting at when he answered that he did not know what happened to those who had BoD but who died without the Sacrament.
Lest people think this is heretical, the precise nature of eternity and the afterlife are one subject about which very little has been formally revealed. This notion of Limbo (along the lines I just articulated for adults, but for infants) was not Revealed, and yet the Church actualy condemned those who condemned it "as a Pelagian fable". It's pure speculation, but it's also not contradicted or ruled out by what has been revealed by God. There's no guarantee whatsoever that God has revealed everything there is to know about all matters.