I know attached solutions for
Hard7 Viscacha and
Hard15 Coypu are intended. Latest update broke their replays, so I just adjusted them a little bit.
Hard9 Chinchilla : This feels intended now

And my previous backroutes still work with some minor tweaks for following levels :
Hard11 Capybara,
Hard19 Mole Rat and
Hard20 RatAnd I think I found new backroutes for following levels :
Hard13 Beaver : I got no blocker solution.
Hard16 Cloud Rat : I still think my first solution is closest to intended so far(connecting basher with 2 builders.)
Hard17 Hamster : several leftover skills