Mortal conviction + Supreme ego + Lone messenger wont work right.....

Herald isn't an aura. It a buff. (Doesn't work)

Lone messagenger disable your aura meaning it not a great synergies for
Supreme ego that let you get 50% stronger aura for 50% extra mana cost.
Mortal conviction (1 Free aura, is also useless since aura are disable)

You can get 1, 50% stronger aura for "free" with mortal + supreme ego. That the only combo that could work here.