Ninjas are quite tricky. They don’t have a mana speed and are best when used together.
I might change it to “maybe” but if the attacker gets red tiles, she may be killed immediately. She is much more dangerous as a left flank.
It’s “rarely” not “no”, but you’re right here. I’ll change it to “yes” when I update the guide next month.
They both summon minions and minions are easily killed with tiles. In the tank position, they are more vulnerable. Freya’s advantage is her realm since she cuts mana when she dies.
Frigg and Odin have a great synergy and are completely broken on defence. If Odin fires after Frigg, the attacker will most likely lose. So the fact that some heroes work well as tanks to broken flanks, doesn’t mean that they are good tanks.