1.) Yes:
Open 24/48 flacs in Mp3Tag.
Select 24/48 files Ctrl+A.
Copy tag info Ctrl+C.
Clear 24/48 file list and add 16/41 flacs (do not close Mp3Tag).
Select 16/41 files.
Paste info Ctrl+V.
Save files.
2) I am sorry, I don't know. You can export individual cells to a file and then reload these cells.
You can also manually bulk edit individual cells:
Select files you want to change.
Replace individual cell.
Save files.