Since Jesus died for all people wouldn't everyone be justified, perhaps even at birth? Since justification is the legal term it seems that it would cover us in Jehovah's eyes from the time of our sinful birth.
If justification doesn't occur automatically when we become living beings when does it occur? Does justification only occur when we put faith in the ransom sacrifice? Then those that don't believe in christ's ransom sacrifice aren't justified? Does that mean Christ didn't die for all, but only for those who believe?
The legal notion of justification is particular and most likely original to Paul (and echoed with some drifts of meaning in post-Pauline literature, whether friendly e.g. Acts 13:38f or hostile to Paul, James 2:21,24f). It is linked to faith (Romans 3:26,28 etc.) and its formal confession (or public declaration, in the NWT) at baptism (cf. Romans 6:1ff). Paul doesn't really mention the "justification" of non-believers, but it is a possible development within the potentially universal scope of salvation (cf. Romans 11:32).
Sanctification; it seems that most of the reading I've done shows it to occur, or at least begin, at baptism. Although I would say that baptism isn't necessarily mandatory (acts 10:44-48).
In some of Paul's greetings (ephesians 1:1 for example) he greets the Holy Ones (saints; hagiazo) and the believers (pisto). Would these believers be baptized or unbaptized? Can a baptized believer not be a Holy one because they haven't been begotten by the holy spirit?
As I said earlier the notions / metaphors of justification and sanctification are different, but that doesn't mean they are not applied simultaneously to the same persons. Note the parallelism in 1 Corinthians 6:11:
you were washed, you were sanctified, you were justified in the name of the Lord Jesus Christ and in the Spirit of our God.