The important thing to note here is Soaring Lightbringer doesn't need to attack for you to get that token
Meanwhile, Yennett, Cryptic Sovereign is one of the most interesting build-around commanders in the set, facilitating a brand-new archetype in odd-converted-mana-cost tribal (while still being fine on its own, with the double evasion making it pretty easy to draw an extra card each turn if you can't cast that card for free), while Varina, Lich Queen finally unites all of the colors of Zombies, so if you are looking to add the white Amonkhet Zombies to the blue Innistrad Zombies on the traditional black Zombie base, she's the best (and only on-tribe) option for your commander
After letting the board develop, you can destroy several artifacts or enchantments and create a hoard of Pest tokens
The best equipment Commander is, like other questions of best card, a matter of personal preference
The white card is basically a white ophiomancer that can Populate