Yes, it's hard to believe that St. Joseph was not in a state of justification. And, in fact, I find it difficult to believe that Our Lord did not teach him about the Holy Trinity and that therefore he had explicit faith in those as well ... but no Baptism, so no heaven.
Yes, exactly. And also St. John the Baptist, Noah, Isaias, Moses, Judith, Abraham and on and on and on. Their justification at death was the difference between them and everyone else that perished during the flood or died during God's wrath at Sodom and Gomorrah and so on and etc.. If they were able to attain justification in Limbo, then so did every single person who died in the OT - including Judas Iscariot.