On Eileen Barker:

Much like in 2 above, many people have chosen to sign up for cryonics based on advice from the likes of Eliezer and Robin; indeed, Eliezer has advised that anyone not smart enough to do the math should just trust him on this.

I believe that most LW posters are not signed up for cryonics (myself included), and there is substantial disagreement about whether it's a good idea. And that disagreement has been well received by the "cult", judging by the karma scores involved.

Several us/them distinctions have been made and are not open for discussion. For example, theism is a common whipping-boy, and posts discussing the virtues of theism are generally not welcome.

Theism has been discussed. It is wrong. But Robert Aumann's work is still considered very important; theists are hardly dismissed as "satanic," to use Barker's word.

Of Barker's criteria, 2-4 of 6 apply to the LessWrong community, and only one ("Leaders and movements who are unequivocally focused on achieving a certain goal") applies strongly.

On Shirley Harrison:

I'm not sure if 'from above' qualifies, but Eliezer thinks he has a special mission that he is uniquely qualified to fulfill.

I can't speak for Eliezer, but I suspect that if there were a person who was obviously more qualified than him to tackle some aspect of FAI, he would acknowledge it and welcome their contributions.

While 'revealed' is not necessarily accurate in some senses, the "Sequences" are quite long and anyone who tries to argue is told to "read the Sequences". Anyone who disagrees even after reading the Sequences is often considered too stupid to understand them.

No. The sequences are not infallible, they have never been claimed as such, and intelligent disagreement is generally well received.

Many people here develop feelings of superiority over their families and/or friends, and are asked to imagine a future where they are alienated from family and friends due to their not having signed up for cryonics.

What you describe is a prosperous exaggeration, not "[t]otalitarianism and alienation of members from their families and/or friends."

There is volunteer effort at Lw, and posts on Lw are promoted to direct volunteer effort towards SIAI. Some of the effort of SIAI goes to paying Eliezer.

Any person who promotes a charity at which they work is pushing a cult, by this interpretation. Eliezer isn't "lining his own pockets"; if someone digs up the numbers, I'll donate $50 to a charity of your choice if it turns out that SIAI pays him a salary disproportionally greater (2 sigmas?) than the average for researchers at comparable non-profits.

So that's 2-6 of Harrison's checklist items for LessWrong, none of them particularly strong.

My filters would drop LessWrong in the "probably not a cult" category, based off of those two standards.