LFR Legion great idea, although Bosses like Aggramar are impossible to defeat solo or even with a couple of friends as you are just knocked off the platform come on guys im sure you had a good laugh around the office at this, some of these issues will persist even once the raid becomes a legacy raid.
Cant kill imonar either. you just get Slept the entire time
Hyrja and Heimdal are possible, but only if you have good movement so you can drag them apart during one of their stand still and cast attacks, or a pet. They have a 99% damage taken reduction buff when they are near each other.