A: If you are planning to actually film or take photographs then you should check out this site for information on when you need a permit- https://www1.nyc.gov/site/mome/permits/permits.page. If - by referring to a popup- you are planning to start a retail business then you need to possibly form an entity first and accordingly you may need different permits. It is best to consult with an attorney so that you get through this process efficiently. Congrats on your new adventure!
A: It will take at least a year to get a green card nowadays- and about 4 months to get the work permit and travel document. Generally, he can travel once he has the travel document. I recommend to work with an immigration attorney so that you can get through this process without any delays. Congratulations!