Below is the answer I have given in other threads. You are already on the way but I think you just need to step back and explore VS/VM then GIT is easy.
If you use option A you just need a shared project which in VS terms is just a project file with .vcxitems extension instead of .vcxproj extension. You should use the visual micro options to "Create a project when adding libraries" simply to see how a shared project looks.
When you see a shared project you should realize that you can just add a .vcxitems file with same name as your library to your library project then you can add it to your solution that also contains your arduino project. Then add a Reference>SharedProject from the Arduino project to the shared lib project. See the readme.txt when Visual Micro creates a shared lib project for you. OR use file>new>project>C++>arduino library.
All VS .vcxitems and .vxcproj files are just text files that you can edit with notepad but you should not need to when you explore the various workflows.
So option A gives you a cross platform library that is GIT capable and will work nicely with your Arduino project(s)
Option B is simpler and gives the library sources below the project. The lib sources are then included in the project/solution explorer as if part of the arduino project. The entire single Arduino project can then be checked into GIT which will automatically include your local libraries. Libraries in the specified location in an Arduino project are treated as normal libraries.
You can use the 1.5 spec or older for libs but they MUST have the library.properties file.
You can also right click a library properties in the "solution explorer > publish library" to have the library "Published to your sketchbook/libraries folder".
The -master is not used because it is just some rubbish that git uses. Normally, you can rename any "-master" folders to normal because both arduino ide and visual micro do some internal rubbish to remove the "-master" rubbish when attempting to resolve libraries
Option A
Create (or let visual micro create) shared library projects (see the checkbox on the "Add Library" menu for an example). Then right click "References" for your your Arduino project and and add the libraries as "Shared Projects". Using this system the libraries can be in any location. There is also a "File>New>C++>Arduino Library" which shows more clearly how a library can become a "shared library project".
or
Option B
You can copy libraries to "project_folder\_micro-api\libraries" and then include them in the project using right click in the solution explorer. You will need to click the little "show all files" icon above the solution explorer to see the libraries you copied using windows explorer. Visual Micro will use the local libraries sources during builds but will treat them as libraries and not local project code. However, they will also be a part of the project as far as any GIT tools are concerned