should I give LA!lyn close counter

yes since u have def + close counter would work if u stack def on her to reach acceptable lvls and given her natural good spd, just decent amount of def will make her a decent tank

Yes! 100% worth it, especially if you use her in an armor team with Blarowl. I use it on my +def Lyn and she can take some hits before going down.

Yes do it, cause IMO close counter is a skill that only a few units can use well, and LA!Lyn is one of those units.

DO IT, especially if she's on an armor team and her defensive stats are being boosted big time.

Give her vengeful fighter as well, and you've got a better W!Tharja.