First, gnomes, traditionally speaking, are flesh and blood creatures
If losing life results in you losing the game, those abilities won't resolve
For years, this has been the biggest problem with colorless artifacts: they give players access to other colors' abilities with ease, which threatens MTG 's balance and could ruin the entire game
You gain life equal to the greatest power among creatures sacrificed this way
Commander Nicol Bolas, the Ravager is the most unique in the game, transforming into Planeswalker Nicol Bolas, Arisen
Most of your characters have good stats for banishing their rivals in challenges, and if they don't there are easy ways to pump them up, either with a song, or as the side effect of a song