Commerce Clause Debate

I'm glad that you can cite the constitution. Maybe you should also have cited clause 3: "[The Congress shall have Power] To regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes", which has been interpreted by the Supreme Court on multiple occasions as applicable to the instruments of commerce, even in intrastate commerce.

Probably some interstate commerce clause justification.

Yes. This falls within the Constitution's interstate commerce clause.

The federal government can claim it affects "interstate commerce".

How is it legal for them to regulate interstate commerce?

The Interstate Commerce Clause says that the federal government has the constitutional authority to regulate interstate commerce, which likely means the federal government could prohibit California from doing this (I say "likely" because "interstate commerce" is complicated and has a long history of court cases). It doesn't say that no state can make any rules whatsoever that affect interstate commerce. Plenty of states have plenty of regulations in place for interstate

It depends on whether the federal law says so, assuming the Commerce Clause permits it. Read about the Commerce Clause for examples.

https://en.wikipedia.org/wiki/Commerce_ClauseConsidering how broadly the federal government has interpreted this historically, arguably regulating far more than simple inter-state commerce, it seems like they could use this to outlaw this kind of activity.

I'm not a lawyer but to me that sounds like a state interfering with interstate commerce.

This clearly falls under the interstate commerce clause, much more so than 99.9% of the laws passed under it.