You've got to be kidding.

(T-teddy vs. H-hedwig)

T-1) Of course, the Grey Lady just happened to be near when Harry needed her.
H-1.Everyone had gathered, ghosts and people, in the Great Hall.
They weren't all that gathered any more. They were evacuating. Harry had time to walk up the stairs, down a passage, sat down with the map and tried to find the duo in the crowd, gave up, put it back, sat with his face in his hands and tried to think, ran back, forcing his way against the traffic through the mob, to the entrance hall, where he found Nick, who pointed out the Grey Lady (chapt 31, pg 614). She was still there, while everyone else was drifting away.
This is the one that's "a little lucky." I give it an 0.3.

T-2) The entire tiara horcrux was beyond lucky. Harry remembering it at exactly the right moment, snatching it up at the last second, but most importantly, out of that entire room of hidden objects- Harry manages to but the Prince's potion book next to the tiara. Or the tiara next to the book.
H-2.That was a little lucky, I suppose.
It was way lucky plus way irrational.
Not only that Harry hid his book next to the tiara (1.0 point), remembered it at the right moment (0.2 point) and snatched it up at the last possible second (1.0 point).
More incredible than that is having it there at all. Forget arrogance -- What kind of an idiot could look at that room and imagine that he was the only one who had ever found it? That's so dumb, I can't even give it points. It's not lucky. It's impossible.

T-3) Hogsmeade- them being near enough to the Hog's Head that Aberforth could cover for them. And that his cover was even accepted at all. They could have had drastically different Patonuses.
H-3.We knew Aberforth liked goats already.
I don't think you were listening: They apperated next to the Hog's Head (0.7). The Death Eaters bought the story (oh-point-eight). AND Aberforth's patronus was a goat (0.4).

T-4) If you think about it- the one group they overhear, that they need, is the one being kept in the Malfoy Manor basement? How many other groups were probably running away from the Snatchers, after all?
H-4.Because the group they needed happened to be made of important, or very close to them people, it's no surprise they had top security.
They did not have top security. They were in the Malfoy's basement, attended by Peter.
They were not that close to Harry and they were not important to Voldemort. Olivander was no longer useful to Voldemort; if anything, he was a liability and should have been dead by then. Luna was just a hostage, being held out of spite. Come to think of it, they had no reason to keep her alive, either.
The two of them had no sensible reason to be there, and they had no reason to be together. I'd give them each a 1.0 for being there and for being alive.
Dean & Griphook -- the odds of their group stopping to rest near the trio's tent already rated a 1.0. And to run into them again -- of both groups being caught by the same snatchers at the same time -- another 1.0.

T-5) Finding the shard of Sirius' Mirror- There being a shard of Sirius' Mirror large enough to still use. I'm suprised under all of Harry's books it wasn't crushed to smithereens.
H-5.The rest of the mirror was smashed to smithereens. And it was hardly big enough to see the eye.
It still was mighty lucky. I'd give it an 0.5.

So, that's how many points for Teddy in this one post? I've lost track -- 8.9?