Lol you guys love these anthropomorphized animals. I do too.
Some suggestions for a more appropriate 5e Character stat block. Most of it is just semantics.
"Creature Type" - I would go with humanoid rather than monstrosity. Unless you intended them to be immune to spells like Hold Person. They also seem just as much a humanoid to me the way you have them portrayed as lizardfolk or other playable races.
"Age" - Most races have an age maximum mentioned. Beavers live to be about 12-15 years old in the wild, so for no particular reason, I'd look at giving them a maximum at about 60.
"Aqua Senses" - This doesn't really translate well to 5e for me. I would maybe change the wording to "You treat dim light as if it was bright light for the purposes of seeing underwater. You might also want to go with "Aqua Vision" instead.
"Proficiency" Look through the list of tools in the PHB and see which ones you think they might get proficiency with...possibly give them advantage with it too.
In your system, I'd guess that talent access being stout might translate to some form of advantage in a specific type of Constitution check under specific circumstances.
Also would the languages be Common and Sylvan? Or Common and Beaverfolk if they have their own tongue?
These are just some thoughts.
Follow the Maztica (Aztec/Maya) and Anchorome (Indigenous North America) Campaigns on DMsGuild!
You're absolutely right about the beaverfolk being humanoid.
age makes sense as well
Aqua vision works for circumstantial darkvision.
Proficiency. need to figure out.
Common /Sylvan works for most fantasy settings. French is an actual language in my world, and it was a silly joke that they are most likely found in the aftermath of canada. :p
I'll definitely tweak it and let you know when it's done. :)