For Bio Seeker, a message pops up in the top left after "Jean used Bio Seeker" for a few seconds. But I'll consider having it do that every time the skill is used, and then have some kind of health bar physically appear (either permanently or for a period of time) if the OT gate is met. Like I said before, I think it can be easy to miss the messages if you aren't expecting them.
Inflicting Dizzy is how you deal the most damage to enemies (kind of like Stagger in modern Final Fantasy or Break in Octopath Traveler if you've played those). Each enemy has 'Vulnerabilities' to certain elements (the attack element icons in boxes under their timer meter) and an amount of 'Guard Points' (the number in the shield). Hitting an enemy with an element they're vulnerable to decreases it by one (though it can be decreased by more if other conditions are met). When that number is reduced to zero, the enemy becomes 'Dizzy' for a period of time, where they receive significantly more damage, skips their next turn, and pauses Rage buildup.
Making the tutorials/mechanics visible in-game is definitely something I'd like to do at some point. It can easy to forget things or accidentally miss them.