Best team with Lyn

trade out Defiant attack for Life & Death and give her Moonbow so Wrath makes it trigger for every single time she doubles for free with Desperation 2. It also lets you actually benefit from Hone Attack on top of the L&D boost since Defiant is a buff effect.

Any WoM dancer acts as amazing support to let Lyn score multiple murders in a match. Other than that, a unit to kill blue units, especially Reinhardt and archers helps. Female Robin with TA and Gronnraven+ and Bowbreaker handles every blue and colorless with no effort and may do so in the same round without buffs thanks to high defensive stats.

If I had to choose, I'd say Lyn, Robin(F), and Azura/Ninian (blue dancer) and the fourth can be an arena bonus or a hero you just like.