I suggest you leave sound effects to the last part of the development of your game, since the scripts can and will vary from time to time, and you'll probably have to re-do some of them, or get stuck with ones you've made in the past.
In the meantime, music and sound effects can be easily replaced by placeholders.
P.D: OGG files are solely used for music tracks, for misc sound files, such as dialogs, weapons, engines, etc, mono wav is used.