My 2004 RX330 has broken flaps on the back of the front seats. The previous owners "little darlings" must have done a lot of kicking to the back of the seats and broke off the fasteners that hold that flap up and cover the under seat wiring. Does anyone have any ideas on how t secure these flaps back in place?

 

You should be able to replace the fasteners or clips with some much easier to find Toyota fasteners from the wreckers.
I would try Highlander or Sienna seats to see if the fasteners match, bring a good one with you to compare.
I paid $2. for a handful of Toyota fasteners at the wreckers.

 

I have the same car with exactly same issues. And I had just found that bottom of the panel was strained by two elastic straps. Beneath the seat, if you look closer, you can loosen the straps by taking off from the plastic hooks. Then you can staple the panel, like what it was, by flipping the panel over. So, this is what Lexus is called "pursuing perfection"? Cheap fastening - That was why Toyota high management quoted more than 10 years ago - Toyota quality is going down, not as strict as before. What he said was true.