I think the biggest issue here would be that the quillboar themselves are most likely to be descendants of the Wild God Agamaggan, a primordial boar that was killed during the War of the Ancients and whose blood appears to have given rise to both the quillboar and the immense thorny vines that created the Razorfen that the quillboar came to call home. Since Night Elves were already around during the War of the Ancients and the quillboar didn't appear until after Agamaggan's death, it seems unlikely they'd fall into the troll -> elf genealogy very well.