It's not entirely clear whether your experience is only with Scala or whether you've used both. If it's the former then I'd suggest that others try Elixir for themselves rather than take a recommendation based on experience with another language.
The points I raised earlier in the context of choosing a language for building a company apply to all of those. I don't see why Elixir is exempt - do you mind explaining?
It runs in a different VM, it's a different paradigm (or mash-up of paradigms which, in turn, is the source of one of your contention points when learning/ramping hires), it's a statically typed language so requires usually more upfront thinking and a better understanding of domain modelling (getting it right from the start), it's notorious for being complex (don't know if it's warranted or not, but it's a normal complaint even from people who seem to like the language).
Elixir/Erlang does need a bit of honest study to hone (this is the same with everything though, JS for instance is quite complex when you take a step back and look at what you need to understand to write decent maintainable code), but the payoff is much higher because it doesn't change with every tide. Code you wrote 4 years ago, if idiomatic, will be idiomatic today, and I'll go off on a limb here and say it will be in 4 years time too.
(btw didn't downvote you)
I'm not trying to derail into discussing how Scala is a shade better or worse than Elixir in some aspect - the main point I'm trying to drive home is that they're both in an entirely different class compared to Ruby/Node/Python.
Your points don't necessarily apply super well.
Point 1 is about hiring and teaching. There's going to be a different candidate pool of people interested in learning Elixir vs Scala, and while I don't know Scala my understanding (heh, see what I'm doing here?) is that it's a pretty large, complex language. So your experience onboarding and training new devs doesn't really apply. In particular your comment about "many ways to shoot yourself in the foot" doesn't resonate with me as an Elixir developer at all. It's a small, simple language, and there's really only one way to do most things.
Point 3 also doesn't necessarily apply. Yes, Elixir is smaller, but for all I know the libraries are better than in Scala or vice versa. I haven't run into too many missing libraries, and the ones we use are generally "production quality", though I don't really know what that means. They have tests, documentation, etc. But again, maybe that's a language culture thing. Dead simple testing, a great doc generation system, and compiler help, combined with general practices prevalent in the community, mean libraries are pretty robust and easy to use. Furthermore, erlang interop is super easy and done a lot. I know Scala has the JVM in principle, but I don't know to what extent you can lean on those libraries, to what extent it's typically done culturally, and to how smoothly they work with the rest of the code.
In short, I think "my Elixir was Scala" is an interesting take and worth sharing. But I think you're leaning too hard on that relationship, without clearly demonstrating that you know Elixir itself, in order to make strong recommendations against using Elixir.