Lisbeth and the title

Yes.

Mikael found the killer without Lisbeth informing him.

But what's great in that? He is an investigative journalist. It's his job to find out/solve a case he's given. He can either succeed or fail. That happens in everyday life.

He has lost a case against someone. He couldn't prove his claims. But, what can he do, his opposition is powerful. We are also familiar with such incidents.

Everyone of us have been wronged in our life at some point. This is also a common thing about our lives. But how many of us plan to pay back the person who have wronged us? Or, how many of us succeed in punishing the wrongdoers?

Here, on this point, Lisbeth turns out to be no ordinary person. She has suffered trauma in her past and she's still insecure about her past, but she will not play the victim. She will strike back in a way you would've never imagined.

She has a dragon tattooed on her shoulder. She is very much like that dragon-we don't know her past or where she came from, but if you make her angry, you will feel her wrath (just like a dragon fires fireballs).

So, this is a pretty common story, Lisbeth makes it extraordinary, with her skills, action, determination and mysterious character.

P.S.: Also it was Lisbeth who did a background check on Mikael for Henrik Vanger. If she didn't have convincing facts from her background check, who knows if Henrik Vanger would have hired Mikael in the first place!

Lisbeth has a more important role than you giver her credit for.

There are several reasons why the English title is what it is, but one of them is that Lisbeth is a central character propelling the action and much of it would not have happened without her involvement. This is clear in the books (and perhaps would have been in the English version of the movie had the original movie been followed, as intended, by sequels). A large part of the action in subsequent books reveals a conspiracy involving Lisbet and her father but also involving key characters who appear in the first book (such as her replacement guardian who not only rapes her but is involved in the conspiracy to conceal the role of her father and the security services clandestine operations).

But even in the English movie, Lisbeth is central in enabling Mikael to follow some of the key clues. She provides the hint that unlocks the bible verses and she provides Mikael with support in his mission in several other ways (plus offering him a route to get revenge on the businessman who won the court case).

Plus she is a more interesting character on which to base the name of the movie than Mikael. Would the English versions of the books or the movie have worked if they were named after him ("Investigative journalist" is his defining characteristic; "Men who hate women" sounds a little too prosaic in English, besides Lisbeth is the central woman who has suffered from that hate!)

Lisbeth's centrality to the events is more obvious in the sequels, but the key hints are there even in the English version of the movie. And, heck, "The Girl with the Dragon Tattoo" is a great damn title.

I think the contribution of Lisbeth to Harriet's case was fundamental, if she wouldn't have provided the biblical citations and the connection to the female deceased it would have been impossible for Mikel to move forward. Actually when this connection was revealed to the policeman ("Oh! they were not phone numbers!!!!!"), he changed his mind entirely and started helping.