The effect of this card activates when it is Normal or Flip summoned and does not state that it has to be tribute summoned. Therefore you can Normal summon this card with Mausoleum of the Emperor with your LP as cost. You can use Totem Dragon or Kaiser Seahorse to tribute summon this card with only one tribute. Or you can special summon him face-down with The Shallow Graveyard and flip summon him the next turn, his effect will still activate.
Depends on the deck you're running, honestly. Photon requires 2 tributes and Feng only 1. Photon stays on the field, while Feng bounces back into the hand. Feng is a level 6, making it a perfect fit in CA with MAAR. Photon is a clunky level 7 that works decently in a Felgrand deck.