Team build

Current team:
Lyn +hp -def w/vantage
Ninian +spd -atk w/hone atk
Robin +atk -res w/swordbreaker
Camilla +hp -spd

Should I replace Lyn with Eldigan +hp -atk?
I also have a Marth +hp -def but he's four star, so I don't know about that.
And I also have a Nino +spd -atk at 4 star, should I get her to 5 star to replace camilla?