I dont suppose it would be possible to allow LFR to count for the necklace unlock in remix? If i wanted to do normal raiding I would do it on the retail servers not on an event thats temporary.
Yes im prolly gonna get roasted by the hardcores and raiders but was worth a shot to ask the devs 
I bought the Hula Doll necklace from Grifta. You cant upgrade the rings/trinkets and necklace anyway. So if youre just going to run LF, buy a grifta necklace to fill the spot.
Then just do the quests and world achievements. That’s my current way.
My suggestion is to either this or giving a blue necklace (eg with 2 sockets instead of 3) from LFR.