Does Bluemix Local have a compute memory high limit of 64 GB? If I have more than 100 App instances, each with a 1 GB memory requirement, how can I run them on Bluemix local?
From the documentation: "Bluemix Local comes with all included Bluemix runtimes and 64 GB of compute memory." https://console.au-syd.bluemix.net/docs/local/index.html#localinfra
Bluemix Local hasn't a 64GB limit. That is the entry level. When you decide to deploy Bluemix Local you should follow a capacity planning requirements which by default is calculated for that entry level.
The minimum to start is 64GB but you can escalate the installation adding more hardware and asking IBM for update deployments in blocks, so at the end you can have what ever memory you need.