I know what they do but I've never used either move.

Here's my question. During battle, can you heal other Pokemon on your team without sending your HealBeller out? Or is it imperative?

The reason is that I wish to use Roselia. It's not a potential fighter but VERY useful. 2 turns to start using Spikes and LeechSeed in that order. Switch out. Keep Roselia out of battle but use Aromatherapy whenever needed.