[Suicide Junkie]

1) The quick-start races might have a problem with being deleted, try removing one & see what happens, but save a backup.

2) depending on the result of (1), you may need at least the original number, but you can definitely add MORE.

3) I believe so, but you can probably ovverride those defaults with specific individual race files.

4) That would depend on the creator's mood & view, but I suspect most modders would not mind if you asked first.