Can I (legally) do this with email?

Hi all, long time no see but good to be back on Fluther. I asked Reddit too so let’s see which community can stir up the better discussion.

Cause laws are tricky, I’m wondering the legal extent of email spoofing, which is making an email appear to come from an email address that I do not control. Particularly if that email address isn’t real. I’m in Indiana if it matters. Examples:

Example 1: I have a company and I want to email people on my subscription list. Say I own the domain mycompany.com but I don’t want to pay for email hosting (ex. noreply@mycompany.com). Since I control the domain and I don’t have any need to see my inbox it would make sense to spoof the email. Is it legal?

Example 2: I attend University X and I want to send some students a link to a survey but I don’t want to use my personal university email. Ignoring spamming concerns and university policy, could I legally spoof survey@x.edu if I know it isn’t already in use by the university? What if it is in use? What if I wanted to survey a different university than the one I attend?

Example 3: I’m planning an event for a friend. He doesn’t want to give me his email credentials but I need to send out the invites via his email. He gives me permission to spoof his personal email address for the sake of convenience. Can I do this legally?

Additionally, are these laws set by the state or federal government? At what point is email spoofing considered identity theft?