Life is a mystery in as far as I understand the writings of the fathers, we have specific things we call Mysteries or sacraments which are the preserve of Orthodox Christians as the Royal Preisthood, these are presided over by those who have been set apart and sanctified by the Church to lead us in worship as members of clergy.
The differentiation in the Ordained clergy is as for as I understand is that they are set apart to serve on behalf of the people of God. Readers and Sub-deacons are the minor orders having specific roles and duties within worship which they are ordained to for fill in the Altar and in leading the singing. Deacons, Presbyters and Bishops compose the major orders and are set apart from the Royal Priesthood to enter the Altar and present the gift of the people not just on the earthly Altar but at the heavenly one. We all participate in the Priesthood of Christ, those who are Ordained do this in a more visible way than the rest of us.
Once we take the view that life is a mystery or as sacramental, we can see it as a continuum form the great mystery of the Eucharist and those associated with it, the other principal Mysteries all happen in relation to this. Initiation (baptism and crismation) originally happened predominantly in the preparation for the great pascal liturgy and almost every time someone is received they receive communion at the end of the service, Ordinations always happen in the context of the liturgy, and originally Marage happened within the context of the liturgy. Monastic toncher happens in the context of the liturgy as it has a close relationship with baptism (though I am shore someone else who knows more about this can explain it better than I can). Of course Confession is also linked closely to the Eucharist in restoring us to the purity of baptism, and the anointing for healing (which was originally in the context of the liturgy) both help us on the path to Theoses which is the aim of all of our spiritual life.
Other things such as the blessing of breads, the blessing of coliva, churching of woman, adoptions, making of caticumins, having our homes blessed and the like are all parts of our spiritual life which sanctify the whole of our life but not specifically related to the Eucharist, and can happen at any service not necceraly at the liturgy. These do need a preist however which links them to the liturgy and the worship of the whole church.
We also have those things which we all do as the Royal Priesthood to sanctify our lives, starting with our prayer life, and including things such as consuming Holy water, fasting, blessing food and drink before we eat or drink, or even blessing ourselves with the sign of the cross. These ones find there full meaning in the baptized, but can and are done by catachumins.
Between these too fall things like oil form lamps and myrrh form icons or relics which can be used by Priests to bless but can also be used by laity to bless themselves or family members, or the venerating relics or icons which we do both at church liturgically and in privet. These things not being excusably for the baptized, however those outside the church gain little benefit form them long turm unless the grace bestowed soferns the heart to true repentance and being united tot he church.
As for numbering the mysteries that is a scholastic thing and although some use it as a short hand it dose not really speak of the sanctifying and transformation of our whole life which is what the Orthodox church calls us to.
As the Mysteries are a continuam so are how much we participate in them, for those outside the church only the things of sanctifying life and veneration of saints are fully open to them, this being deepened by becoming a caticumin, the only of the major mysteries open to those outside the church being initiation to receive them into the sacramental life of the Church. As we grow in our faith we participate in the mysteries more deeply and fully, this process never ending as the mystery of God is never ending.
I hope this helps, and those of you who know these things better than I do feel free to correct me where I have got things wrong or explained them badly.