As for Theosis vs Justification and Sanctification.... vs?
Lutheran theology, insofar as it reflects the Augsburg Confession, is still too Roman (Western) for Orthodox tastes. The big difference (please don't take offense; none intended) is the Western view of Original Sin, which is that Adam's guilt is inherited. In the Orthodox view, it is the effects of that sin that we have inherited, as well as a proclivity to sin, living, as we do, in a fallen world. That difference also affects how we view justification and sanctification, of course. Do be aware, however, that Orthodoxy is not, repeat, not Pelagian. We know that theosis depends upon God's grace. Everything does.