・25% of the amount of Bravery/Faith raised or lowered during battle will be carried over.
・Changes in multi-player quests won't be carried over.
・The amount of raised or lowered Bravery/Faith by abilities such as Final Hour won't be carried over since that ability has turn restrictions.
Placing your units in the guild barracks will automatically increase their bravery every hour by 1, up to 70.
Since Faith works differently, the game lets you adjust each unit's Faith to your liking. You can adjust their Faith by tapping the "-" button on the bottom right of each unit squares.
You can increase your units' Bravery and Faith manually by buffing their stats in battle. This can be a fast and efficient way to increase them, especially if you plan on making them ready for pvp or guild battle without much time.
The best mission to do this is on the mission "Concerns", from Chapter 1, Scene 3, and first mission. It's the best place since the team spawn location is grouped up, allowing you to buff the entire team using each Meditation, or Faith Rising.
In order to raise your unit's Bravery, you'll need to use Bravery increasing skills, preferably one that works in an area. Most Samurai jobs have Meditation, so you can use any character with a Samurai main job or subjob. Be sure to level up the Meditation skill.
Next, put the units with the bravery increasing skill on slot 3 (and/or 4 if you bring 2 units), and give them agi increasing equipments and esper. This is so that they get to perform their actions first before your team. You can also unequip your teams' equipment to slow them down.
Once the battle starts, simply use the skill and buff your teams and press auto to complete the fight. The AI won't use Meditation even if you disable all of the skills except it, so you pretty much have to manual the fight a little.
Units with a Samurai job have access to Meditation. If you never levelled up any units with a Samurai job, look for one that has it as their main job. This is so that you don't have to level/awaken them up at all, except for the skill's level.
Tidus is a free unit that comes with the FFX collaboration, which can make it a lot easier for most people to be able to do this without any gacha characters.
When it comes to Faith, unfortunately, there is only 1 character (as of updating this guide) with an area Faith increasing ability, and it's from Kilphe. However, Fina has a single target Cheer ability.
Basically, a unit in the front lines with physical attacks should have high Bravery and low Faith. It can then deal more physical damage, have a higher chance of activating reaction abilities, and take less magic damage.
However, if you want that unit to gain more HP from healing abilities, it should have high Faith.
A unit in the back lines with magical attacks should have high Bravery and high Faith. Then it will deal more damage with magic-type abilities.
Abilities such as Divine Healing and Chakra are physical, but the amount of restored HP depends on Faith of the caster and target.
but its worth it to have good faith even if the character dont do magic damage. If he does some status effect, faith will affect the effectiveness(more chance to afflict it) and you recieve more healing from self healing or from another healer. so some physical character can have high faith. Your personnal choice