Silvershield Knight is a big NO! It dies too quickly against magic, which is very common. He is great in melee mayhem or sneak though, just not at the tank position.
Sacred Unicorn is your best option in unarmored and melee-only. Werewolf is great and it's trending. Clay Golem with enraged is your best bet when healing is disabled, but it's also good in melee-only and on the last spot in sneak.
Werewolf might be even better than Palading in level 5 and beyond, but Paladin reigns supreme up to level 4.
Good points. Silvershield night can tank but only sometimes haha. He is fast but only if you know you're not running into fast magic.