Yes this should be possible. The two different plug-ins could be installed on the same machine and should not interfere with each other. Underneath they both perform the same functions, e.g. they both call the same plcncli commands under the hood.
Edit: Actually now that I think about it some more, it might be more complicated than that. The Visual Studio project will include a .sln file and .vcxproj file, and the Eclipse project will include its own project files. But these might not interfere with each other, if the IDE-specific files have different extensions (and I'm pretty sure they do). It might take a few tricks to get both IDE projects set up on the same source files, but once that's done I think it should work OK.
Allright, in that case I will investigate and update this post after! Thanks.
We have chosen to use visual studio code and defined the needed plcncli commands in tasks. That way I am still able to build with hotkeys and have the nice interface of VScode 
In addition on this, I thought I have seen the vsix file for C# programming somewhere in the folders created by the toolchain installer. That way it would be possible to also make VScode capable of creating C# libraries I guess. I suppose it was in the ide-plugins folder one time.. Where can I find that file to check if it’s possible to use VScode? Or should I configure that a different way / is it only usable in Visual Studio 2019?