Oh wow! So different from my perception! Very interesting... Very very interesting... The Scutter/Seras combo does also sound very fun.
I'm personally having difficulties winning with Urso and Krogg in Calamity mode. In normal mode everything is possible, basically, but Calamity is really another matter.
Woad and Mabek at the end of the list is bonkers to me! XD They are incredible for me.
There is one thing that maybe I didn't explain enough: my perception was based a lot on "starting with them", in calamity mode. Because if you, for example, find Urso later on, when you can immediately evolve it and give it food, then you are good to go (still not as strong as others for me, though), but starting is tough.
In general, I'm personally having trouble at the start, for calamity. Less trouble (but still challenging) in the middle and trouble again in the end, with the final boss and some normal/elite enemies of the 3 zone.
For these reasons, the initial stats and strategies are way more important for me than the middle/last ones. Even I die early, in the end, or I don't, most of the time.