Solidify Echoes of Majesty Past

When you hit the threshold of a Major Power, is the effect in addition to the base effect?
Yes, unless the card says "instead", threshold effects are in addition to the base effect [p. 17].
(Discussion elsewhere) Tags: Elements, The Jungle Hungers, Tsunami, Vigor of the Breaking Dawn, 27 more...

Can "Tell the Old Stories" restore Powers forgotten or replaced prior to the start of play? (e.g, Boon of Vigor with the Sunshine Aspect)
No.
Tags: Forgetting, Tell the Old Stories, Sunshine Aspect (River Surges in Sunlight), Solidify Echoes of Majesty Past, 5 more...

When an effect lets you play a card, does that count against your allowed number of card plays?
No. The number of card plays on your Presence track only affects how many cards you can play as part of the "Play and Pay For Power Cards" action in the Spirit Phase. Cards played any other way (usually in the Fast Phase when instructed to do so by a Power) are in addition to those limits.
(Discussion elsewhere) Tags: Playing Power Cards, Spur on with Words of Fire, Unlock the Gates of Deepest Power, Gift of the Primordial Deeps (Serpent Slumbering Beneath the Island), 14 more...

When an Aspect starts the game with a Minor Power in its hand, does that Minor Power count as a Unique Power (e.g., for Tell the Old Stories)?
No, it's still a Minor Power.
The type of a card never changes, no matter where it starts the game. If you're ever unsure which type a Power Card is, check the back of the card.
Tags: Tell the Old Stories, Dark Fire Aspect (Shadows Flicker Like Flames), Violence Aspect (Bringer of Dreams and Nightmares), Warrior Aspect (Thunderspeaker), 4 more...
If a Unique Power Card is transferred to another Spirit and then Forgotten, which Spirit is eligible to get it back via an effect that re-gains Forgotten Unique Powers, like *Tell the Old Stories*?
Any Spirit that has had that Unique Power Card (whether in hand, in play, or in discard) at some point during play. This may mean that multiple Spirits are eligible to re-gain a particular Unique Power Card.
Tags: Forgetting, Transferring Power Cards, Entwined Power, Tell the Old Stories, 2 more...