Here is my thought for what it is worth.
Yes, the TRZ bushing is a nice peice, have them in my Cutlass.
Funny thing, my "ears" were to narrow on the stock 12 bolt, had to make a spacer, go figure!
But can you survive with out them, yes.
The arms you have already have joints on one end so they will move pretty freely.
It appears your car is set-up for mostly drags?
How much movement is your rear really going to have to worry about bind.
Do you a anti-roll or beefy swaybar?
The most my rear travels in 2 inches , it can move more but that's what the rings on the QA1s show.
Put it together and get racing!