For points 2 and 3 this is crucial if you're recording for a show with a young demographic (preschool etc) as children understanding concepts clearly is a major directive

Also general tips based on who I see casted (I've worked on shows for a particularly large and mousey studio):
1) Your mic doesn't have to be fantastic but make sure everything is clearly understood in the file
2) Be aware of regional accents and words that may be distinct
3) Enunciation is key