I would say on the battery issue that devices divide themselves into two classes:
- Ones that come apart with a guitar pick. These have a seam on the side which can be worked. They may be difficult but after you take them apart they simply snap back together again.
- Ones that use adhesive tape. These have a metal back that wraps around and a tiny crack between the edge and the faceplate. They can be difficult to take apart and the only way that they'll be the same afterwards is if you remove all the old tape and put new tape on.
https://www.microcenter.com/product/...tape-4-mm-wide