As for regular 40k I can hypothesize that I've played more than you as I'm not the one asking for a tzeentch list that is also competitive.
22 years of 40K gaming behind me. Nice try but you fail.
You started out cool with some awesome conversion ideas but I've lost any respect I may have had for you as this thread has progressed.
You have blatantly disregarded the fact that I have stated several times this will be played in a store so the scenery will be spread across multiple games and tables so I can be pretty danm sure my opponents will HAVE to spend a few turns in the open. You are clinging to this ludicrous idea that you will always ALWAYS have cover which is just bollocks unless your table is 90% scenery with literally 1" bewteen it all.
Rather than look at the challenge presented, which was TRY and create a competitive Tzeentch list you jumped on the RARGH QUARTET high horse and have blinkered yourself from actually being helpful.