Seeking your advice/Best way on Windows Installer / Builders to redistribute the NuGet Dlls - From windows Installer - VS2010

Our Scenario is We are building VS 2010 Setup Installer (Setup and Deployment project )  which install  Visual studio custom project templates , some add in and  our code -custom dll in GAC and artifacts for add ins .

Till now we were using .net frame work-4.0 dlls to build our software , so  pre requisite would be present in customer in client computer as part of net frame work 4 . Despite of the tradeoffs of putting in GAC , we have been adding our custom dll in GAC, (Installer project – File system Editor- Our Project output to GAC) and everything is working.

 Recently  we started using Newtonsoft  , Active Directory Authentication Library  for our new requirement

Since Microsoft  does not provide anything for distributing our DLLs outside of the NuGet gallery, seeking your advice on Windows Installer / Builders to redistribute the dll Newtonsoft  , Active Directory Authentication Library  in client computer

Options

Approach 1) : Make this open source dlls  as pre requisites  : As part of customer instruction manual for our software – we can include nuget package commands of open source dlls -Newtonsoft  , Active Directory Authentication Library  

                             However customers are free to download the package, unpack it and GAC  the individual DLLs in assembly and we also  would like to validates pre requisite exist or not client compute by writing below code

                             Question 1)   Is this best approach to follow  ?

                              Question 2)    If yes  , what would be the best approach to determines whether assembly exist from below code ,,any other best ways .

                 /// <summary>

        /// Does AssemblyExist

        /// </summary>

        /// <param name="assmblyName">Assmbly FullName</param>

        /// <returns></returns>

        public static bool DoesAssemblyExist(string assemblyFullName)

        {

            bool isExist = false;

             //LoadWithPartialName is Deprecated         

            //Assembly currentAssmbly = Assembly.LoadWithPartialName(assmblyName);        

            try

            {

                string assmblyName = "newtonsoft.json, Version=4.5.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed, processorArchitecture=MSIL";

                // Approach-1

                Assembly currentAssmbly = Assembly.Load(assemblyFullName);

                if (currentAssmbly != null)

                {

                    isExist = true;

                }

                // Approach-2

                //or

                isExist = Assembly.ReflectionOnlyLoad(assemblyFullName).GlobalAssemblyCache;

                //or

                var assemblies = AppDomain.CurrentDomain.GetAssemblies();

                // Approach-3

                var assembly = (from a in assemblies

                                where a.FullName == assmblyName

                                select a).SingleOrDefault();

                if (currentAssmbly != null)

                {

                    isExist = true;

                }

            }

            catch (Exception)

            {

                //Log

            }

            return isExist;

        }

Approach 2) : GAC this dll from our  installer (Right click - Set up and Deployment project  - File system Editor- Configure to GAC this dlls )

Approach 3)  : I am not sure we can configure VS2010 Setup & Deployment Project: to put DLLs into /bin folder  because we have 7 class library (c#) project output dll  which we are adding to GAC from Setup & Deployment project  and waiting for the  approach on Newtonsoft  , Active Directory Authentication Library

Best Regards Showkath