A:AnswerReplaceable yes, swappable no. Important distinction.
If you need to repair your battery by installing a replacement it's fairly to do if you has the replacement battery. It is an hour job maybe.
Which means you need to disassemble and disconnect various components to replace the battery and won't be something you swap for convenience.
A:AnswerNo. There is a bell but no other safety accessories included. You would need to consider buying a speedometer, helmet, mirrors, etc. in addition to the scooter.