Holiday Yufine

S2 - Reduces the effect of decreased Combat Readiness debuffs inflicted on all allies by 50%. This skill effect does not stack with other passive skills of the same name. Increases Evasion by 35%, and increases Evasion by an additional 35% when the caster is at max Health. If the caster get effected by skill with reduce Combat Readiness when the caster is at max Health, dispel one debuff from the caster.

S3 - Dispels two debuffs from all allies and attacks all enemies in the middle of the night market. Increases Attack of all allies for 2 turns and Combat Readiness by 20%. This skill cannot trigger a counterattack.

EE (ATK+14%)

S1 - Increases the chance to inflict Burn by 20% (85%)

S3 - Additional reduces the effect of decreased Combat Readiness debuff inflicted on the caster by 50% (100%)

S3 - Additional the effect of increases Combat Readiness by 5% (25%)

I think she has potential in current meta against ML Politis. Build her with high speed + Taeyou's AF. But she is easy to trigger enemies' counterattack because all her attacks are AOE. So at least add no counter on S3 will help her.

Sol Badguy

EE (ATK+14%)

S2 - Activate Volcanic Viper(S2) against the enemy uses a non-attack skill instead of attack that targets all allies. Dispel one buff before Volcanic Viper.

S3 - Ignores Effect Resistance of any targets with Attack lower than the caster's Attack.

S3 - Increases damage dealt by 15%

He can potential to kill Jenua even most of the most Jenua hidden in stealth. If you can go first and grant him ATK buff, he can kill Jenua without soul need or 15% RNG. Also if Jenua's immortality up and activated S2 with Sol S2 EE, he can dispel immortality and hit Jenua with Volcanic Viper. Can also use him against other heroes with non-attack skill + extra turn. The silence from Volcanic Viper can interrupted them.

Luna

S2 - Increases Critical Hit Chance, Critical Hit Resistance, Attack and Defense by 30%.

For me, I still think Luna doesn't need much buff. She isn't meta but still usable in PVP and still one of the best for PVE DPS. The main issue for me while using her is her Attack+30% part than need to has HP 50% or more. I build her with SPD DPS but other DPS are faster. When her ally kill enemy, there a chance to get AOE counterattack and the main issue is Karina S2 activate and overlap Luna > S3 her ally > Luna loss her ATK 30% from splash damage. So just removed the condition is already a huge buff for her. Increase DEF+30% permanent is also great.