#1 - You tried to have a unit with 2 brillance aura, and they didn't stacked?
(You can try having them different buffs or Id, you can also try having one of type 'item' and one of type 'hero'.
#2 - You want that when a unit is loaded in another unit, it gain faster mana regen?
The SAME ability cannot stack, but if you have 2 different abilities both with different buffs, they can stack.
As for 2nd, you'd need a trigger that runs when that unit loads a unit - it increases the level of brilliance level. Then another trigger that runs when it unloads - it decreases the level.
Ghan has said he has fixed this. Monovertex please confirm this fix. This was only a problem with people that had signatures in the upper levels like not the special members but the respected members.