Reading through the "Four Marian Dogmas" in the context of our Lutheran Confessions, there are really only three things that we would take issue with.
The first being the fact that these things are Dogmas, that is more or less, articles of faith, in that Scripture does not mandate these beliefs as such.
The Immaculate Conception is at odds with with Scripture which tells us that Christ died for all, not all but Mary; likewise Mary speaks of her "low estate".
Also, the "god like" attributes which they afford Mary; not only are not supported by Scripture, but if they were true would take away from the all availing sacrifice of Christ.
Scripture, from our POV seems to support Semper Virago, but does not, out and out state it is so.
There is no debating that she is Mother of God, considering God's narration of Christ's incarnation in Scripture.
While Scripture is silent regarding the Assumption, there are "extra Biblical" texts which, while questionable, do give testimony that this was believed very early in the Church; as such it may be held or it may be rejected. Our Church commemorates the Feast of St. Mary, Mother of our Lord on exactly the same date as the Feast of the Assumption in Rome.
For me, I accept and believe that Mary is ever virgin; she is the Mother of God. I'm on the fence regarding the Assumption; but I must admit that if Christ willed her assumption, it would be so.
Do I believe that salvation is contingent on faith in these things? Nope!