Is it legal to work as freelancer while employed at expedia for some extra bucks? Working After hours for developing software for any client?
There are visa considerations for US as well.
Search up moonlighting laws for your state. That should answer your questions. In general, not official legal advice, you are allowed to work additional jobs if there are no conflicts of interests, conflicting work hours, and does not negatively affect your main job.
You're allowed to work conflicting work hours, negatively affect your job, have conflicts, etc. That's just unprofessional, not illegal.
Probably depends on the state. But most likely it’s allowed if there’s no conflict of interest
You don't say what country you're in but there is no US law prohibiting having as many jobs as you want. If you were working in some cleared national security capacity you'd have an obligation to disclose the other jobs but that's not this. Have fun