Thanks for the advice!
I really like your shirt plan there, and the little hanging suspenders in #4. The shirt shows off the tubbiness of Knuffel...
I'm also loving the mouth idea- I'm thinking having him start sticking his tongue out in stage 4.
Off-the-shoulders is good because thylacines really only have stripey butts, their front paws don't have the pattern. shoulders was my compromise for striping, though lower stomach might get some too, especially in stages 2 and 3.
I might have a tied belt in stage 3, rather than a buckled one.
Also, beaded hair starting stage 2 and going forward.