Faerie Fire and Sacred Flame
Going by the books, it would not grant disadvantage.
Faerie Fire grants advantage to attacks directly against it. I believe this is mainly due to the glow that would make it easier to see them? Since Sacred Flame requires them to dodge the attack and not the attacker hit them, it would not fall in this category.
Most of the publications would state if saves or the like would gain disadvantage as well. So if it's not mentioned, typically there's no change to it.