A skyBeacon/tailBeacon can legally be used to enter and exit United States airspace. Pilots must also be familiar with and comply with the destination country’s ADS-B rules if applicable. At this time Canada, Mexico, and the Bahamas do not have any ADS-B requirements for light aircraft.
Yes, the position lights need to remain switched on during all operations. Removing power from the position lights also removes power from skyBeacon and/or tailBeacon. According to 91.225(f) “Each person operating an aircraft equipped with ADS-B Out must operate this equipment in the transmit mode at all times.”