Replacing a worn RTAB (Position 3) Makes a massive difference to the way the car drives just make sure you get a wheel alignment afterwards. I can't say if a Powerflex is better than stock as I went from a crusty worn part to a powerflex unit and it stiffened things up massively.
As for if you need to do both the RTAB and the Lollypops at the same time not sure, if they are worn I would say it wouldn't hurt.
I have also done the ARB bushes 2 and 4 on your drawing, not sure how much of difference they made as I did then when I did the RTABs.