I know what you are going through, because the side air bags were a must-have on my wife's shopping list for a vehicle.
Starting in '06 power seats are standard in Sport Edition models (they were previously optional). Power seats were always standard on the Limited models. For SR5 models - they are optional/part of certain packages.
I didn't find Autotrader helpful when trying to find a model with side airbags. It seems like the dealer didn't always mark them/list them separately, so if you are trying to sort models by that specific criteria, you will have a hard time doing so.
I ended up buying an '08 - and as already mentioned, '08 models and up the side airbags are standard across the board. However, when I searched, if I found a 4runner that I liked, I just looked at the pictures - 2 giveaways (if the side airbags are not listed by the dealer) are a gray tag on the front driver and passenger seats, just above where the curve stops (a little over halfway up the seat) and also a button on the dash to the left of the steering wheel labeled "RSCA off". There are 4 black button/button covers to the left of the steering wheel, and on models with side airbags, the "RSCA off" switch enables the driver to turn off the side airbags (for off roading situations). If you see that button - you know the 4runner has them.
One other thing I noticed... mostly for SR5 models, power seats are much more common on V8 models. Not sure if this is just how the dealer ordered the vehicles, or if they were part of a common package or what, but this is just an observation.
Hope this helps!