I can see why give the statue to the opponent so you can get Raviel back to hand, but you still need 3 tributes to get him back on the field. Something like Tsukuyomi or that Lv12 Subterror monster to flip down Raviel is better so you can re-flip summon Raviel once per turn work better.
Is this correct? Since we got subterrors, I have been able to get the mats by flip summoning monsters to get their mat. Maybe the game has glitched on me? Your description sounds accurate for summoning extta decks monsters from the GY.