Lin

*Lin isn't an amazing healer, but she's not-bad. She has other things to do.
*When her HP hits 70%, she casts 2 shields on 3 allies with the lowest HP. This can be used in Ashwood as this skill triggers even if she dies (1 of the 3 units in this case will be herself, however). This skill also finds uses now and again against event bosses.
*She debuffs enemy Crit Rate by 15% and Crit DMG by 30%. This isn't normally something we use with her somewhat-weak healing.
*She buffs MSPD by 30% and ASPD by 15% for all allies, something Wedding Lin does already and more. So use WL unless you need the shields or crucially need the crit debuffs.