These cards have their merits, especially if you prefer a more competitive approach to Commander, but if you find yourself conflicted about including them, its completely justifiable to keep playing what you enjoy instead
In Vintage, you can even grab a Mox or Black Lotus
While a double-faced card is on the stack or battlefield, consider only the characteristics of the face that's currently up
For example, if you control Johann, Apprentice Sorcerer ("Once each turn, you may cast an instant or sorcery spell from the top of your library") and Brightcap Badger is on top of your library, you can cast Fungus Frolic, but not Brightcap Badger
Each Battle enters play with a certain number of counters on it, sort of like a Planeswalker card
It blanks indestructible, ignores death triggers, and laughs at graveyard recursion