Android Messages is apparently [1] the renamed "Messenger", the Google one (the internal android APK names are the same), which was probably confused with "Messenger" the Facebook one, likely to Google's detriment and Facebook's gain. Renaming it probably salvages some of that confusion.
Also, Hangouts "the original" (aka. the Hangouts App, Chrome Extension, Chrome App, Gmail Widget, and the standalone website) -- most of which will probably live on. The extra irony is that the same time Hangouts App users are being warned to move to a different app for mobile text messages, GTalk users are being told to switch to Hangouts, while Google Voice users are being assured that their Google Voice texts (and presumably calls) will keep working within the Hangouts App, even though a new Google Voice App was recently released that mysteriously added chat.
Also, Hangouts "the original" (aka. the Hangouts App, Chrome Extension, Chrome App, Gmail Widget, and the standalone website) -- most of which will probably live on. The extra irony is that the same time Hangouts App users are being warned to move to a different app for mobile text messages, GTalk users are being told to switch to Hangouts, while Google Voice users are being assured that their Google Voice texts (and presumably calls) will keep working within the Hangouts App, even though a new Google Voice App was recently released that mysteriously added chat.
Then there's Allo, Duo...
[1] http://www.theverge.com/2017/2/24/14721602/android-messages-...