@PikaPixi Do you have the Lime Profile downloaded? Mochifitter will need that as instructions for how to retarget(resize) the outfit for you.
Import MochiFitter into your project, then Import the Lime MochiFitter Profile. You should be able to find that in the thread I linked.
Up at the very top of Unity, there should be a MochiFitter tab. Click that and have it download/install the Blender addon provided.
Download the Manuka Version of the outfit. I linked that. Select the Manuka Profile and Lime profile in the MochiFitter window.
Drag in your outfit prefab into the MochiFitter window's space provided. Press "retarget outfit". Wait for it to finish. Press okay on the window that pops up, then it'll automatically go to the folder with the retargetted copy of the outfit. The name will start with "finalized".
Plop that onto Lime in the hierarchy
I'm saying all of this from the top of my head so of anything isn't specific enough, let me know. I'm not at my PC rn but I can give better instructions when I am.