There are two rites here. One is the sacrament of the Anointing of the Sick, and the other is the celebration of Viaticum.
During the course of the Church’s history, the anointing of the sick (which had originally been all about healing, not about impending death) became associated with the last moments of a person’s life. Therefore, up until Vatican II, the sacrament (which had become known in the Latin rite as ‘Extreme Unction’) was administered only to those for whom death seemed imminent.
With Vatican II, though, came a change. In the 20th century, theologians were already discussing the original meanings of the sacrament and its Scriptural basis, and so there was the desire to return to some of these meanings. The name of the sacrament was officially declared to be “the Anointing of the Sick”, and it was declared to be appropriately received by anyone who, through old age or serious illness, felt the need for healing. Many Catholics, however, still associate it with the moment of death. (So does Hollywood, whose films still perpetuate this perception of the sacrament.) Paul VI wrote the Apostolic Constitution Sacram unctionem infirmorum, describing the sacrament, and approved the updated order of the rite (Ordo Unctionis infirmorum eorumque pastoralis curae: ‘the order of anointing of the sick and of their pastoral care’).
The Anointing of the Sick can take place in the context of the Mass, or it can be outside the Mass. The Church also has a ritual for anointing in a hospital or institution. The ritual for the Anointing includes a Liturgy of the Word and a Liturgy of Anointing. The Liturgy of Anointing includes a laying on of hands and an anointing.
Viaticum, however, is part of the pastoral care of the dying. It is Eucharist that is “food for the journey” (which is what ‘viaticum’ means), and it is meant to strengthen the Catholic who is preparing himself or herself for their passage from this life. (Please note that viaticum is different from communion to the sick – in that context, the Church includes the ill person in the community celebration of the Eucharist and prays for their health; viaticum, on the other hand, is expressly part of the pastoral care of the dying.)
when in danger of death, Q1 - the priest also administers The Apostolic Pardon ( I read)which means that all temporal punishment (time in Purgatory) is eleminated.
In fact, the celebration of Viaticum is expressly meant as part of ministry to the dying, for those in ‘proximate danger of death’. This celebration can contain a number of features: a renewal of baptismal promises, a penitential rite (or the celebration of the sacrament of Reconciliation), a Liturgy of the Word, a Liturgy of the Eucharist, and of course, reception of Communion. Depending on the state of the person, there may be no opportunity for such a celebration of the sacraments; in these cases, an abbreviated rite may be utilized.
The Apostolic Pardon, which you mention, can be part of the celebration of Viaticum. Following the celebration of the sacrament of Reconciliation (or following the Penitential Rite, if the person has recently celebrated the sacrament of Reconciliation), the priest may give the ‘apostolic pardon for the dying’ to the person. He does so by way of praying one of these two prayers:
“Through the holy mysteries of our redemption, may almighty God release you from all punishments in this life and in the life to come. May he open to you the gates of paradise and welcome you to everlasting joy. (Amen.)”
“By the authority which the Apostolic See has given me, I grant you a full pardon and the remission of all your sins in the name of the Father, and of the Son, + and of the Holy Spirit. (Amen.)”
So, to answer your question: yes, the apostolic pardon remits all punishments that Purgatory would purge from a person’s soul. And yes, there would either be the sacrament of Reconciliation immediately preceding the pardon, or the person would have already celebrated the sacrament of Reconciliation recently, prior to the celebration of Viaticum.
Q4 - I did ask an educated Catholic who was under the impression that an Apostolic Pardon forgave all sins including mortal sins?
The intent of the rite is that the sacrament of Reconciliation is celebrated prior to the apostolic pardon. Therefore, the intent of the pardon isn’t to forgive sins, but to remit the punishment due to sin. Implicitly, the forgiveness of sins occurs prior to the pardon.
Q4 - Is the Apostolic Pardon always included in Holy Viaticum when in danger of death and as an official part of the Roman Rite for Holy Viaticum.
It is not a required part of the ritual, and it is at the discretion of the priest. Some priests may be relatively unaware of the apostolic pardon.
Q5 - Is the Sacrament of Reconiliation intrinsic to i.e. part of Holy Viaticum? (or only if the person desires to receive this Sacrament)
It is not a required part of the rite of Viaticum, but it may be celebrated within the context of that rite.
Q6 Is The Apostolic Pardon conditional on freedom from mortal sin?
It is presumed that the person has celebrated Reconciliation, and therefore, there’s no ‘conditional’ nature to it.