We are a long way off topic so I’ll answer but keep it all hidden:
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I hadn’t levelled the Richard or Quintus that I already had from before costumes; still the case now so haven’t used either.
Horghall I had levelled to 3-70 already (second ever 5* hero); so have levelled the costume to 3-70 also but only for the stat boost & his use in the Trials of Fortitude.
Elena I have levelled both Costume & Base hero. Use her all the time in my Red Raid Stack in tandum with Black Knight (See here for Riposte & BK synergy)
Lianna I have levelled to max +7 emblems; costume maxed also. I predominately use the costume as in my Green Stack I focus on DoT so the mana slow is more useful than more damage for me.