Reading this thread, I saw the exact problem why I stopped coming to XDA-developers. Such snobby people who don't actually care for real advice. How many times did people suggest Awesome Icons? Yet no one responded to them.
By the way, I use Nova but I have an S8 and I want to be able to change the stock icons so that the icons in my Apps Edge match my Nova icons. Ever thought of that?
Couldn't agree more. I am too looking for a easy solution for this.
I have found a work around, little messy but does give the desired end effect.
Using tasker, create a task to launch the app you want to have in your app edge. Once set up test it so it launches when task is executed.
Next set an icon for the task, this is what will show in your app edge.
Next install tasker app factory, and export your task as an app and install it.
Now you have the app to put in your app edge that will go nicley with your theme.
If your struggling with getting access to your icons from your packs, extract them and manually find the icons you want.
Pros- looks like it has been nicley themed.
Cons- long, tedious and have 2 of every app in your drawer/apps list (although you can hide the original app in your drawer if your using a third party launcher, so no Biggie)
But it does work ? just had to re set up my s8+ on Oreo. Will be doing all my app edge apps agin over the next few days. Can show picture as I go if needed.
Btw, you can also use this method to customise your lockscreen icons too (left and right bottom app icons)
One last thing to mention, Samsung stock icon pack seems to give a rounded effect on icons that can ruin this effect. I have found a free third party icon pack in theme store that removes this. I can link this too if needed.
Sorry for the long post

I had intended to do a YouTube tutorial ages ago for this, but since I've had my second baby I don't have time sadly.