The summer sale drops RIGHT after I spend on the premium 50% off gacha....

I guess I'm going to add more 6* girls to my arsenal / harem.

I could also use some advice: currently I have the following:

Slice: Wax Vine / 2x Fritillaria
Hit: Dendrobium & Pumpkin
Pierce: Ionocidium
Magic: Dogwood

Should I go for girls to even my 6* spread? What are good future-proof Pierce / Magic choices?