DB4 in Lilina?

I...don't think so? Having a B.Celica+1 is better than having 2 more in-combat attack on Lilina isn't it?

I would say no. I think skill refinery is going to happen soon and the +2 isn't much needed. You still kill about everyone,

It is if you want to use Lilina a lot. If you aren’t going to use her consistantly, then no it isn’t worth it. Assuming you are planning to build and use her, DB4 is pretty good on her, but what other units do you have that could take it instead?

Wait until the next update (3.0.0) and see what that has to offer. There might be an easier way in getting DB4 without sacrificing a B!Celica for it. Otherwise, if you plan on using her quite a bit and get her to +10 then yes, I'd suggest putting DB4 on her. While Res is good, you would want something like +Atk on her if you're going for DB4... that'd be a waste of a Celica if you didn't max out her attack.

Lilina is a glass nuke. If she doesn't kill off the target odds are she's getting killed off. That "Extra 2 damage" can mean the difference between living and surviving the battle. When initiating you get +14 attack and at +10 with +Atk IVs you're sitting at 72 attack without buffs or a special. Give her something like Glimmer and she can be incredibly devastating. Plus Forblaze gives -7 Res to the highest Res target.

Edit: Do not fodder off a merged Brave Celica for the skill... A single one can be questioned, but a merged one is just a very bad decision.

Let me get this straight, you are asking if it's a good idea to fodder a +1 brave celica, a 5* exclusive with good performance and excellent fodder, for a lilina that's not even +atk?
Did i get that rigth?