I'd say no since that is a good roll Minerva. Tough it out with Life and Death 2 (4* Hana), and settle with +4 atk +4 spd for now until another option opens up to you.
I assume Linde is +Def and -Res? That Minerva has pretty decent IVs, so I personally would not sacrifice her unless you get a Linde with better IVs or you have more than one Minerva.
I wouldn't. That's a really good IV set for Minerva. I have a similar situation; I rolled Jaffar (+spd -hp) and I've been building up my Setsuna, but I stuck with LoD2 for her that I got from Hana until I can get LoD3 from somewhere else that's not as valuable.
I wouldn't merge since those are some nice IV's on Minerva. Plus Life and Death 2 is good enough and it's more of a budget skill since Life and Death 3 hardly makes a difference and it requires lots of investment to get the full tier.
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