How do I lower the rear seats if I dont have the button things?

 

I don't think even Cadillacs have rear seats that "lower"
You mean "fold" the seat back?
There should be a latch in that corner, unless you have a special "trim" that hides it. If you do, then, you'd may have to find a long tool to push down OR pull up on the mechanism hidden inside that upholstery. (I hate hidden fasteners and latches.)

 

You need to source the "buttons'' from the junkyard and screw them in, if you stick your finger in there you'll know what i'm talking about, after you do that just pull the knob up and that's it.

 

But B4 you try to fold the back seat down you'll have to pull the bottom seat up from the pull strap attached to it, you can see the bottom seat pull strap next to the seat belt buckle on either side of the seat. Pics stolen from Google.

 

it'll look like this.

 

Nice illustration and clean 4runner, maco35!

May we know what thread that screw is and how long in order to be able to grab it from above and outside the upholstery?

O.P.,
IF you could not find the "button", just find a screw of same thread and right length and that should do the job.

 

I got a couple from a 2nd gen. 4runner as they are the same as our 1st. gen.

 

#5 is mine, in my driveway.