Let's say that I determined the best course of action is using the Help action to give my Rogue buddy an advantage on his attack instead of attacking by myself. Would that attack then gain the sneak attack bonus since he's at attacking at advantage?
Sneak Attack says:
Once per turn, you can deal an extra 1d6 damage to one creature you hit with an attack if you have advantage on the attack roll.
The Help action says:
If your ally attacks the target before your next turn, the first attack roll is made with advantage.
Sneak Attack can be used if the attack roll is made with advantage (or an enemy of the target to be with 5 feet); the Help action gives that advantage, as long as the rogue is the first ally to attack the target (and the advantage isn't canceled out by disadvantage). It's that simple.