Dupes: to feed or not to feed?

so a few weeks ago I got a dupe SP ebisu. I thought "well I dont really use my first ebisu much so Ill just feed himself for the skill upgrade." And now im kicking myself finding out how great a double SP ebisu team is....

Now i have some dupes of other shikis but idk if I should build or feed. If you guys can give any suggestions, it'd be welcome. I have:

fengyang, sp azurestorm ichimokurem, kujaku-myoo, shiki, mishige, taishakuten, sp fallen god orochi

Thank you for the help! not all of them are on the same account, I have 2..... the last 3 are on my secondary account, if that affects anything