English translations for "stimmig, rund"

This is not about some translation job assignement as I'm not a translator. Just something that came up the other night in the pub, where I acted as a sort of translator between German and Dutch friends who chose English as their means of communication (and me as there little helper translationwise).

Unsolved problem #1: Das Konzept ist einfach nicht stimmig, das ist nicht rund.
All I came up with is stuff like 'doesn't add up' , but that's not really what stimmig and rund convey.

Unsolved problem #2: Klarer Fall von Futterneid. It's a word taken from behavioural biology and sometimes used figuratively in German. Surely there must at least be an equivalent used by biologists in English, even if it's not used out of context there?

Any thoughts?

Thoughts, yes, but I don't know if they're any good.

#1: doesn't hold water / is unworkable / doesn't fit?

#2: food envy? (if I understood the German term properly)

Stimmig = coherent

Futterneid...don't think there's an equivalent compact noun in English, Kays food envy comes close.

ahhh i'm up to my eyeballs in translations!!! good thing i'm not doing german-english.

i'm stuck with english-spanish, english-korean, english-japanese, english-mandarin

You're translating from English into all those languages?

This certainly lacks finesse but for #1 I would say it just isn’t quite right.

Thanks for your replies, people

Let's say you wanted to find a translation for stimmig, rund (not for nicht stimmig, rund) - any ideas there?

The Futterneid thing doesn't seem to appeal as much as Schadenfreude and Weltschmerz (though I think Futterneid should have a place and a word in any language, it's so fundamentally human).