What would be the best refinement for LA!Lyn's default weapon? She's Spd+/HP- and more Speed never hurts, though with her naturally high Resistance a Res+ can help her survive even green mages like Nino since the Gift weapons nullify the buffs.
I would still go for the speed refinement to give you a better shot at doubles and to help deny doubles from other units. However, I would pair her alongside two units who offer fortify and hone armour buffs (with her using armour march for movement) to boost that resistance and her speed to Ayra levels.
I run Ward Armor for my Armor team to give them a better shot at surviving and to avoid Panic Ploy, but she is still using her bond skill because of how versatile it is. She has Desperation 3 on her, which is very nice since she can one-shot even green mages if she has Iceberg ready to go.
I might give her Ally Support with Winter Chrom(Atk+/Res-) so that being close to him gives her some extra boosts and he can cover her weakness to axes much how I paired my LA!Hector(also Atk+/Res-) with my Winter Tharja(HP+/Spd-, +3 merged) to cover their weaknesses.
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