This app was mentioned in 16 comments, with an average of 1.75 upvotes
There is an App for that which works pretty nicely (it has some bugs for WhatsApp though, don't think it's their fault). I have been using that because Quick replying is so handy.
Note though that you pretty much have to pay for the app, as it has a character limit on the free version, which makes it super annoying to use.
https://play.google.com/store/apps/details?id=com.jamworks.quickreply
I just got Nougat today, and know now that the App I linked is still inferior to Nougat's implementation, but it's still a nice app
When it comes to direct reply and overall look of notifications, you can change this so that notifications look like on Nougat and you can also direct reply. You need:
Xposed with the Android N-ify module.
An App called QuickReply
This is as close as you can get to Nougat without using nougat when it comes to notifications.
I use the App quickReply and it works pretty damn well!
Note though that you pretty much have to buy the paid version, as it's pretty useless otherwise (only lets you type a few words until it prompts you to buy the app)
This app will do it for tons of communication apps:
https://play.google.com/store/apps/details?id=com.jamworks.quickreply
This has been a nice compromise for me after rolling back.
Here's one, Idk if cross platform. Android is easy, apple is hard.
https://play.google.com/store/apps/details?id=com.jamworks.quickreply
I just typed floating chat into Google play.
Not sure if it works with Textra, but I use Quick Reply with WhatsApp and it does what you describe - a very good app!
Ohhhh. You mean this?