Is it possible to include PPT on a RTW?
 

I know AF does LAX-PPT, but can I backtrack the return on a RTW? Can I do like LAX-PPT, then do PPT-SEL which would actually be PPT-LAX-SEL on AF and KE?

You should be able to, as long as you are continuously going in one direction (east or west) from stop to stop. Frequently, backtracking is the only option available.

I have been out of the industry for a couple of years so don't take this as gospel but ... most RTWs specify 1 transpacific and 1 transatlantic journey - by my reckoning you have 3 transpacific journeys here so I would so no
( you would also be chewing up a lot miles )

Also ,you haven't said where you are starting your journey - if in North America then I would very much doubt that you would be permitted to return to your continent of origin and then continue your trip

I would be starting this RTW in Europe and will take either Skyteam or Star. Thanks for the advice so far.

Yes you can fly that route because flying to lax i the only option to get to ppt on skyteam, and i know it because i done it before but you cant make a stopover then you have to fly within the 24 hours to sel.It is the same with syd/akl if you wanna include those the only option is KE so you always have to fly back to sel.Just a note i dont know when you wanna make your tip because if you gonna use star there wont be a LAX-PPT anymore from april with because NZ is gonna stop that route then.