You don't need to learn C# but it could help, and it's not bad anyway - bit like Java.
If you can handle Qt/Qt Creator you can handle VStudio, but signals and slots are not VStudio
Yeah - called C++/CLI. Herb Sutter's baby. It's C++ on top of .net and so produces a .net application and not 'standard' .exe. It 'extends' the C++ language to include topics such as 'boxing' etc for managed .net objects. IMO if you want to use .net you'd be better off learning/using c# which is designed for .net.
There's also now C++/WINRT for Windows 10 (any platform). See:
I try to avoid using the 'Universal Windows Platform" dreck. Mostly from lack of desire to learn the API. Keeping up with the changes to standard C++ is a bit daunting when doing the self-taught routine.
I prefer the Petzold Win32 API approach. As clunky as that can be. MS changed the Win32 API in enough places that code from his 5th edition requires some updating/rewriting.
Windows apps are complicated enough, compared to C++ console apps. I am not planning on developing apps for Windows devices other than a regular Windows PC desktop.