Should I spark for Izana ??

[Zetura]

Considering my main team is free Resna, breaker Marie, fire Ryza, Rorona and Sophie I could replace free Resna to cover 3 elements instead of 2.
And also considering I have Lydie and bolt Resna, I can make a team that would buff her well for harder content potentially.

[Am]

If you are F2P and can't save quickly, at least save them a bit later. Rose FES is almost here, featuring Rose units of Valeria, Heidi and Flocke back to back all the same elements(strike).

Though from my own usage, bolt Resna and Lydie should be rainbow units(even though they are bolt). Your Ryza and Rorona should already be in good hands.

So my advice, if you REALLY like Izana then yes go and spark her. You'll farm her cores and that will also take a while, so spark and start making your strongest hammer girl. Hammer girl all the way.

last thing, replace your free Resna with Lydie or bolt Resna.