Erasimus, are you still having issues with that multibind? The issue is likely having an item and an AA in the same multibind, but I know there were two patches around the time of that post that adjusted EQ multibinding rules.
That having been said, I generally opt to not include Firebound Orb or Force of Elements in a multibind. Firebound Orb will fire whenever it's up, and that can lead to it consuming the Conjurer's Synergy proc during the GCD between RS and Of Many if multibound.
Force of Elements has a cast time, and depending on when it refreshes, it can end up casting at the end of a GCD such that by the end it finishes casting, the GCD has been over for a few tenths of a second. That's not huge, but it does cost you a few spell casts over the course of a raid event that Force does not make up for. Beyond that, with the amount of lag often present in modern raids, it actually takes much longer than 0.5s for Force of Elements to fire. If you find Force of Elements is not firing smoothly (especially during burns, which are often most laggy), it is better to use it less frequently than to not cast your primary damaging spells that do far more damage.