[Moto G4 Play Questions & Answers] stephen.george.west:
pre reboot:

shell@harpia:/ $ pm list packages -d
package:com.amazon.clouddrive.photos
package:com.imdb.mobile
package:com.google.android.apps.messaging
package:com.motorola.att.phone.extensions
package:com.amazon.mp3
package:com.amazon.now
package:com.google.android.apps.inputmethod.hindi
package:com.amazon.dee.app
package:com.amazon.drive
package:com.google.android.apps.inputmethod.zhuyin
package:com.motorola.motosignature.app
package:com.motorola.genie
package:com.amazon.avod.thirdpartyclient
package:com.google.android.inputmethod.korean
package:com.motorola.msimsettings
package:com.google.android.inputmethod.pinyin
package:com.amazon.phoenix
package:com.google.android.inputmethod.japanese
package:com.motorola.easyprefix
shell@harpia:/ $

Post reboot:

lock screen has the lady with the telescope "discover your next book" background, is back wall paper is still on my chosen wallpaper.

shell@harpia:/ $ pm list packages -d
package:com.amazon.clouddrive.photos
package:com.imdb.mobile
package:com.google.android.apps.messaging
package:com.motorola.att.phone.extensions
package:com.amazon.mp3
package:com.amazon.now
package:com.google.android.apps.inputmethod.hindi
package:com.amazon.dee.app
package:com.amazon.drive
package:com.google.android.apps.inputmethod.zhuyin
package:com.motorola.motosignature.app
package:com.motorola.genie
package:com.amazon.avod.thirdpartyclient
package:com.google.android.inputmethod.korean
package:com.motorola.msimsettings
package:com.google.android.inputmethod.pinyin
package:com.amazon.phoenix
package:com.google.android.inputmethod.japanese
package:com.motorola.easyprefix
shell@harpia:/ $

hmm. this reboot i noticed that my background didn't switch back to the default for about 30-60 seconds. I compiled a version of 'run-as' to re-enable the package. I re-enabled the ads like so.

shell@harpia:/ $ ls /data/local/tmp
dirtycow
run-as
run-as+
run-as-
shell@harpia:/ $ /data/local/tmp/dirtycow /system/bin/run-as /data/local/tmp/run-as-
shell@harpia:/ $ /system/bin/run-as
Package com.amazon.phoenix new state: enabled
shell@harpia:/ $ pm list packages -d
package:com.amazon.clouddrive.photos
package:com.imdb.mobile
package:com.google.android.apps.messaging
package:com.motorola.att.phone.extensions
package:com.amazon.mp3
package:com.amazon.now
package:com.google.android.apps.inputmethod.hindi
package:com.amazon.dee.app
package:com.amazon.drive
package:com.google.android.apps.inputmethod.zhuyin
package:com.motorola.motosignature.app
package:com.motorola.genie
package:com.amazon.avod.thirdpartyclient
package:com.google.android.inputmethod.korean
package:com.motorola.msimsettings
package:com.google.android.inputmethod.pinyin
package:com.google.android.inputmethod.japanese
package:com.motorola.easyprefix
shell@harpia:/ $

Then lock the screen. The Telescope lady is gone, and the notification ad is back.

I can then re-disable the package:com.amazon.phoenix, and both are gone.

shell@harpia:/ $ /data/local/tmp/dirtycow /system/bin/run-as /data/local/tmp/run-as+
shell@harpia:/ $ /system/bin/run-as
Package com.amazon.phoenix new state: disabled
shell@harpia:/ $ pm list packages -d
package:com.amazon.clouddrive.photos
package:com.imdb.mobile
package:com.google.android.apps.messaging
package:com.motorola.att.phone.extensions
package:com.amazon.mp3
package:com.amazon.now
package:com.google.android.apps.inputmethod.hindi
package:com.amazon.dee.app
package:com.amazon.drive
package:com.google.android.apps.inputmethod.zhuyin
package:com.motorola.motosignature.app
package:com.motorola.genie
package:com.amazon.avod.thirdpartyclient
package:com.google.android.inputmethod.korean
package:com.motorola.msimsettings
package:com.google.android.inputmethod.pinyin
package:com.amazon.phoenix
package:com.google.android.inputmethod.japanese
package:com.motorola.easyprefix
shell@harpia:/ $

I think something else is in charge of initial lock screen background when the normal adverts are not available.