Huawei Nexus 6P :: Peeking And Lockscreen Notification

All I want is "peeking" and the lockscreen notifications to work! Isn't this part of Marshmallow? Notifications to be not working/ inconsistent? What I am looking for is to have the screen turn on with every notification...this phone is either sitting on my desk or in a car holder most of the time, so I want to see the notifications without having to handle the phone. I've tried some 3rd party heads-up notification apps that work pretty good, but I am having issues with the lock screen (sometimes I have to enter and pin AND use the fingerprint scanner, which is a bit much to just access the phone).

1. I seldom get peeking notifications even though "peeking" is selected. With some apps, peeking works sometimes and not others. I have never seen a Peek notification for gmail.

2. I find the notifications seldom turn the screen on, even though I have the ambient screen turned on. Perhaps this has something to do with problem 1.