I turned off all my email notifications except the VIP folder, where I keep the very few people who might need immediate attention. Settings > Notifications > Mail. I do leave badges on, so that I have a rough idea of how many emails I haven't looked at yet.
But all you should have to turn off to prevent the light is Show On Lock Screen. Though if you don't like light, you probably don't apprecieate sounds either, so turning off Notification Sound is another.
But, if you want all these things on, except at night when you are trying to sleep, then Johanna's suggestion about the Do Not Disturb settings is best. You can even schedule it.