In the past I was sometimes asked to do this outfit, but always gave people a link to someone else's version. But, in the end, why not? The other one is hard to find anyway and I figured I might be able to improve on it.
This outfit reminded me that Sims2 normals just don't translate directly to the Sims 4, so I used an online site and steps found in the Sims4Studio forums to remake them. The result is what was in-game for the Sims2, so it was a success!
The hands are another area of contention. The Sims 2 just doesn't have as many joints for hands as the Sims 4 (although the other joints all have equivalents). For normal hands a straight-up replacement is best, but the Bunny here has mittens. I didn't want to make them unmoving flippers, like the animal costumes in 4, so I wound up subdividing the whole thing and using CAStools to apply the vertex groups. Then I just stitched the hands onto the mesh I wanted to use (since CAStools tends to destroy a mesh when it makes UV_1s). In the end I'm happy with the result.