Why not have a single function that uses a router? Just map /* to the function and within the function, make your calls to other discrete handlers.
First thing I always do is read the quotas/limits on any google cloud product before I use it.
Then, I'd notice the increase in deployment times on my CI server as more functions were being added and inspect what was taking so long and try to optimize it. Those individual endpoints take a while to deploy...
Once you get past a certain amount of endpoints, I'd always want to declare my endpoints in code rather than be tied to their config.
Never had an issue with the logs. Requests still show up.