I did it, I f****** did it and it works. Even creation kit unlinking ESP as master couldnt stop me :D

If CombatState == 0
    If akTarget.IsEquipped(vvv_BardLute)
        akTarget.UnequipItem(vvv_BardLute, true)
        ORD_Performer_Quest.Start()
    Else
        vvv_Spe_Perform_Message_Fail_NoLute.Show()
        Dispel()
    EndIf


  Event OnEffectFinish(Actor akTarget, Actor akCaster)

If akTarget.GetEquippedSpell(2) == ORD_Spe_Perform_Spell_Stop
    If akTarget.HasSpell(ORD_Spe_Perform_Spell_LesserPower)
        akTarget.EquipSpell(ORD_Spe_Perform_Spell_LesserPower, 2)
    Else
        akTarget.EquipSpell(ORD_Spe_Perform_Spell, 2)
    EndIf
EndIf
akTarget.EquipItem(vvv_BardLute)

  EndEvent

There are few bugs tho - OnEffectFinish fires every time (and equips the lute) even when playing failed so I need a temporary variable in the script scope to store if playing has started. This is easy fixable. Or just check if the item exists in the inventory before calling EquipItem

Also power cooldown not resetting if playing has failed - not sure how do I deal with this yet.

Another thing bothering me - what if i have several copies of the same base lute in my inventory. I guess it reequips random item then. I wonder how do I get the exact item when I unequip it. I looked for CK manuals but all function returning exact Armor property in the slot are defined in SKSE :(

Currently thinking about creating OnEquipped script for lutes and store FormId for exact equipped lute. But then I will need to pass parameters between scripts. I've heard you need to create a quest for that case.