This is a small business so costs have to be kept under control. Since I have all the appropriate server licenses for the 4 server instances, what VMWare licenses would I need to do this and where can I find good advice on developing a robust system?
The vSphere Essentials Plus kit satisfy your requirements and still leave a free license to an third ESXi host.
Take a look here for details: VMware vSphere Editions and Kits Comparison | United States
