It depends on how much effort it would take to rewrite any of said components.
In my personal experience, for reasonably isolated and small components, 80% of time spent creating a component of code is spent on making decisions. By the end of it, when all the decisions have been made, I could probably rewrite the entire thing from scratch in 20% of the time—and it would likely be better in every way.
It would seem that the first iteration is largely prototyping. If you can save a significant multiplier of time by choosing a different language than the rest of the stack for the prototype and potentially rewrite it later if necessary, why not? Perhaps by the end of it all, you'd break even on time but end up with multiple implementations and better code.
In my personal experience, for reasonably isolated and small components, 80% of time spent creating a component of code is spent on making decisions. By the end of it, when all the decisions have been made, I could probably rewrite the entire thing from scratch in 20% of the time—and it would likely be better in every way.
It would seem that the first iteration is largely prototyping. If you can save a significant multiplier of time by choosing a different language than the rest of the stack for the prototype and potentially rewrite it later if necessary, why not? Perhaps by the end of it all, you'd break even on time but end up with multiple implementations and better code.