I would say Limbo. Clearly the theologians cited by De Lugo distinguished between justification and salvation (as Father Feeney did), but I don't recall or haven't read what they say about someone who would hypothetically die justified but not saved.
So my answer is Limbo. Father Feeney simply answered "I don't know." I am unaware of whether these other theologians dealt with the question at all.
Fr. Feeney from Bread of Life:
...He will then say, "If you die in the state of justification, without yet being baptized, are you not saved?"
You must answer him, "No, you are not. 'That is your reasoning in the matter. That is not Christ's statement."
And if he persists in saying, "Well, where does one go who dies in the state of justification which has been achieved without Baptism?"—insist that he does not go to Heaven.
And if he goes on to yell at you angrily, "Where are you going to send him—to Hell?", say: "No, I am not going to send him to
Hell because I am not the Judge of the living and the dead. I am going to say what Christ said, ‘He cannot go into Heaven unless he is baptized by water.’
It is important also to add, "I am making an act of Faith. You are not. I believe in Baptism because Christ revealed it, not because I have also figured it out by my own notion concerning the intrinsic requirements for justification..."