In E:wom I was able to trigger quest events from a champion's level. Note the unit's internalname used, which means each quest is specific that internalname.
<TriggerType>UnitLevel</TriggerType>
<TriggerStringData>Emperor_Karavox</TriggerStringData>
<TriggerData>7</TriggerData>
<TriggerOrigin>CapitalCity</TriggerOrigin>
<TriggerChance>1</TriggerChance>
<PostTriggerChance>5</PostTriggerChance>
Worth testing in FE, if any modder is up for it.
Are you up to it? <grin> You've just introduced many new heroes in Stormworld, after all.