Iksars start dubious with Indigo Brotherhoos unless you were killing orcs in Crushbone. DE merchants are apprehensive at start, and their faction is easiest to fix, with
Red Wine quest in Neriak 3rd Gate. The quest gives positive hits with Neriak guards as well. For iksar monk / shaman took 40 stacks of red wine to make max ally with Neriak vendors and apprehensive with guards inside and outside the city. Nero/SK, clerics and casters will still be threatening, but are easily avoidable with invis/FD or if you know your way around the city