1. It's only the free Hypervisor edition which is limited to 32GB physical memory. However, even the low priced Essentials Edition will not only remove this limitation, but also unlocks the API to allow e.g. image based backup applications. Never forget backup when designing a solution.
2.+3. Overprovisioning is not a bad thin per se. It depends on the workloads and how you configure the VMs. In most environments I built, the CPU is overcommitted and I didn't have any issues with this so far. When you take a look at the CPU usage on a typical ESXi host, you will notice that host CPU isn't used as much as you would expect.
André