We recommend no more than 4 options when creating a BLF, as too many options would be too convoluted for any calling user. So for personal assistant, we have limited this to 4 as this is an end-user managed feature.
Default would be the destination if no option is pressed.
This would be a free-option. It would solely depend on the business if they want to have this available. Maybe there is somebody, likely a receptionist monitoring parking with Sonata Switchboard, and can locate parked calls. Maybe you can re-route calls with parking to a receptionist extension, as well.