Its not hard to deduce what this means
Trade haste for lifelink, then remove one toughness, first strike, and ward and you get a very similar monster
+1/+1 and trample to the whole board is definitely the one that you can get the most mileage out of, but if your board isnt wide enough for that to matter, you might be able to take advantage of the mana or draw a card, and the worst case is that you gain 3 life -- which, while not amazing at first, is the kind of thing that when triggered over and over can make it pretty hard for your opponent to take you down
This allows the pair to synergize with counter-based synergies and flickering effects alike
For just one mana, a creature will gain +1/+1 and hexproof until the end of the turn
I like God-Eternal Kefnet here as well, as it allows you to essentially cast your spells twice