There is not enough information for me to answer the questions.
From the regulatory perspective you would need to determine that yourself and have whatever testing is required for your local authority.
If you are talking about manufacturing a device, with or without modification to the open hardware design, you are free to do so, but you cannot call it an IoTaWatt. That name is a trademark of IotaWatt, inc. and can only be used with hardware manufactured and tested by that company.
The firmware is distributed under a different license. That license is referenced on the Github site, and the requirements to include the original copyright and license are specified there.
If you are not considering modifying the hardware, many of these issues can be eliminated by reselling the hardware manufactured byIoTaWatt, and it is possible that local regulatory compliance can be satisfied, in whole or part, by testing that has already been done and certified.