1. Mary is to be prayed to,
Absolutely.
2. she is titled "Queen of Heaven",
She's nothing less than your queen.
3. Marian apparitions are sought after
They exist, and should be taken seriously into account. Whoever denies this should do some serious investigation on the matter.
For instance, on October 13th, 1917, Fatima was confirmed by an unprecedented public miracle, the Miracle of the Sun, which occurred at precisely the moment the peasant visionary Lucia said it would. More than 70,000 people, including Masons, communists and atheists, saw the sun, contrary to all cosmic laws, twirl in the sky, throw off colors and descend to earth. The event was reported in newspapers around the world, including the New York Times.
4. she is said to be the only human sinnless like Christ
You're correct. She's our Immaculate Mother, the sinless New Eve.
5. she is considered by many to be "co-redemptrix with Christ" for the human race
Her mission as Mother of the Messiah was no less than Coredemptrix. Of course, it must be rightly understood. This title is only proper once it is understood that she participates under the only Redeemer such as we mediate through participation under the only Mediator when we pray for others. Such as how we participate under the only Son of God when we become children of God.
6. she is so exaulted that the "immaculate conception" miracle - (having a sinnless child) is attributed in Catholic tradition to HER mother giving birth to HER.
The Immaculate Conception is not attributed to Anne. It is attributed to God preparing the Mother of the Messiah for her exalted work of Mother, Coredemptrix, Advocate, and Mediatrix.
So is this simply mariology - or is it mariolatry?
Well Mariology means "Study of Mary", so if you're studying the truths about Mary, then it would be Mariology. If you are worshipping Mary by giving her the adoration that is due to God alone (latria), then it would be mariolatry.
Considering that you haven't mentioned giving the adoration that is due to God alone above, we cannot impute the gravity of mariolatry in these instances.
The question is asked on another thread - how does this differ from ancestor worship and praying to the dead?
Well, Mary isn't given the adoration due to God alone, so we can't say that idolatry is being comitted, and Mary isn't dead. She's alive with the living God in heaven, interceding for you, her child.
We fly to your patronage, O Holy Mother of God:
despise not our petitions in our necessities,
but deliver us always from all dangers,
O Glorious and Blessed Virgin.
(The most ancient Marian prayer we have; 3rd century)
Mary, how sweet is your name, pray for us, your meek children, and show unto us the fruit of your womb, that we may be made worthy of the promises of Christ and echo your Fiat through our humble lives in imitation and service of your son.
God bless,
Carson