In your case, strength training is of the utmost importance. This may sound odd—training your pokémon to get stronger and all—but in truth, strength training also involves a lot of discipline. By helping your incineroar and bewear to grow stronger, you also help them familiarize themselves with the way their bodies work, which in turn allows them to understand how to apply weaker amounts of pressure if needed. You may also wish to target precision specifically by having them attack specific targets, rather than use all of their force in order to achieve a particular goal. Either way, be vigilant during your training exercises and be sure to guide your pokémon into understanding that control, rather than pure strength, is the key to success both on and off the field.
Once they grasp this, having them show affection to your sylveon should be rather simple.
Your sylveon, meanwhile, might need to be taught a bit of restraint—especially if his charisma has anything to do with his fairy-type abilities, such as Baby Doll Eyes—but by and large, it may be more effective to target your bewear and incineroar’s levels of discipline, especially given the fact that this is their teammate.
Best of luck!