The second mode drains your opponents, and the third gives you card advantage for each opponent with one or fewer cards in hand, which is relevant if your deck is built around making your opponents discard their hand
Noctis is a good Commander, sure, but its also sweet in any Esper artifacts list
Feral Encounter Having to play the creature the same turn you case Feral Encounter adversely impacts its ability to be played early (cant use it early, have to have enough mana to play it as well as the creature that turn) making it questionable inclusion in your cube
An extra turn might not seem that amazing considering you won't have much mana left the turn you cast this, but the real power is that it gives you the opportunity for all your other creatures and planeswalkers to provide extra value
This also skirts around the aforementioned issue of being stuck with symmetrical card draw when its down to just you and one other player
Which one was your favorite