Note that this library only supports scaffolding one function at a time per process - so you'd have to create a separate process [and use a separate port] for each function you're using. (This includes event-based functions - everything is HTTP under the hood, and this library is no different.)
2) Deployment time - you're definitely not the first to bring this up. :) We're working internally on improving deployment times.
(Disclosure - per my username, I work at GCP.)
[1] https://cloud.google.com/functions/docs/running/function-fra... [2] https://www.npmjs.com/package/@google-cloud/functions-framew...