Is this true for squad members?

Thane is still an good choice for this mission. I often take him and Miranda. Having him want to stick to cover on this mission isn't necessarily a bad thing, since the biggest problem I can have during it is running out of medi-gel reviving fallen squad mates. The first battle can be a real bitch since there is very little good cover available for the three of you and the collectors are not shy about trying to flank you. Also, the Assassin's can just rip through your shield/barrier like butter and drain you right out of health in a blink.

It's not really Thane's weapon damage that you'll be relying on... it's his warp, along with Miranda's for stripping barriers, and his throw (which can detonate warp) and/or throw any mooks without barriers right off the platforms for you. Jack can also be a good choice if you've done her loyalty mission and she has warp ammo available. Her shockwave can throw a lot of collectors off the platforms, as well as detonate warp, overload and cryo blast. If you're not playing on insanity, she is also really great for handling the husks near the end of the mission (If you're on insanity, they are all armored, so that diminishes the effectiveness of Jack's shockwave in this portion. I can't remember if they are also all armored on Hardcore.)

What is your bonus power

Also, you will be able to select a "bonus weapon training" before the first fight.  If you pick the Sniper Rifle Training, you will be able to use your own Viper if you want to bolster Thane's long-range weapon damage.

I think the page is right. At least in my experience it always worked better to give squad mates harder hitting guns rather than fast firing ones. I always give Thane the Incisor and he seems to drill head shots quite easily.

That's the weapon I give to him if I recruit him. It's also the weapon Zaeed and Garrus use as well

Well Zaeed and Garrus already use the Incisor, so I thought of giving Thane the Viper, but it turns out that he and the rest do not benefit from the Viper. So he will get the Incisor as well.


Upggrade

Thank you very much for that info.