I have an 05 with rear air suspension. I installed a 2.5" Toytec adjustable lift only on the front suspension. It's like the one you linked, but probably an older design. Rather than swap out the rear air bags with insulators and new coil springs, I kept the AHC and merely adjusted the height sensor to level the rear ride height even with the front. The benefit is that I didn't have to spend anything to lift the rear.
Of course, there have been several people here and on Facebook Sequoia discussion groups who have performed the full swap, which as I mentioned above is very straightforward. The spring seat on the axle is already compatible with standard coil springs, and since the air bags attach to the frame, you need only to replace the bags with the insulators in order to provide a place for the top of the new coil springs to seat securely.
I do not have first-hand experience with how much lift is attained using the Toytec rear springs, but since the front springs have adjustability, I imagine that it would be pretty easy to level it all out with the front adjusters only. BTW, get an alignment after you complete the lift.
I'm sure there are several ways to disable the AHC, but I haven't specifically looked into which method is the most desirable to disable it, since I intend to keep my fully functional AHC system for now. The airbags are only 4 years new, with fewer than 70K miles on them, and the feature is frequently put into use when I tow. I do not plan to do frequent severe off-roading that will require extreme axle flex that is possible after installing taller springs and shocks and removing the rear sway bar. For the occasional times when a rear tire lifts due to insufficient axle travel, I have a rear ARB locker to help put power on the ground. My Sequoia is built as more of an expedition vehicle rather than a rock-crawler. My other 4x4 is built up for that purpose.
I hope that helps.