If you could get mother north or Vivica with costume, which would you max and put emblems on? Why? They both are slow tanky heroes with one healing less, but has revive. The other can debuff or cleanse and do a defense up or down stat while healing more.
Tough choice.
Not really tough. Momma is clearly the better hero
I have Vivica. I don’t have Mother North. I would trade Vivica for Mother North any day of the week, and twice on Sunday. So… pretty clear cut choice there, all else being equal, Mother Norse is the winner. 
(In my opinion. 
)
Good gaming!
With her costume Vivica is great. She provides some great flexibility, & that strong defense down from a yellow hero is unique as well.
That said, if you’re lucky enough to have Mother North you have a hero with one of the most coveted skills in the game with that ability to revive. And while her heal isn’t as strong as Vivicas, it also produces minions as shields to help supplement it.
I don’t think it’s quite as cut & dry as the previous responders, & I don’t think you can really go wrong either way. That said my personal experience is limited here. I’m fortunate to have costume Vivica, but she’s still at 3.70, and I’ve never been lucky enough to pull Mother North
Maybe consider the rest of your roster and decide if you’re lacking in either color, or if a healer in one color allows for better combinations elsewhere. Either way, good luck. It’s a good problem to have
If you running yellow tanks in wars I will give symbols to C. Vivi.
If not, MN is better choice
I am lucky enough as a c2p person to have both. Love MN… use her in most raids. She is even better with emblems. don’t have Viv’s costume that certainly improves her but there are other def downs, very few revivers