A hat I made keeps crashing my game

Hi. The blend you import in the package must contain only the hat, the body parts are included in the rig which you must not touch.
I started to explain how to delete and unwrap everything but then decided it would be faster to start a new package, export the blend, delete ears, and create new ones. Just this time make sure to check Generate UVs and set Cap fill type to Triangle fan.
- Clone the same animal hat, export the blend, select one ear, and collapse it (Alt M - collapse);
- in object mode create and position a cylinder,  check Generate UVs and set Cap fill type to Triangle fan ( make it less high poly than it is right now);
- create and position a torus(again, less high poly);
- once positioned, merge( ctrl J) both but not with a hat;
- click on + icon, double click on the group's name, rename it to b__Head__, select everything with A and click assign;
- duplicate and mirror the mesh;
- in Edit mode select the duplicated ear and Mesh - normals - Flip normals;
- vertex paint them with 007F00;
- choose a uv_1 map,select everything and W - Weld, put somewhere in the corner;
- choose a uv_0 map and move the uvs somewhere to the side;
- Shift select the hat and Ctrl J;
- choose a uv_0 map again, select ear uvs, set a background image, S Y .5, put uvs in the spare space near hat's uvs ( which you do not touch).

Also, for the future, before trying to make anything, watch/read a few start-to-finish tutorials to have basic understanding of what has to be done. It can be any CAS part, the process is identical for the most part. CC making is, unfortunately, not as straight-forward as one would wish