State regulations, local regarding manufacturing, FDA compliance and familiarity with laws as applies to cosmetic.
Following IFRA guidelines is optional, not law.
Some sell online and take a risk, but there are fines or at least cease and decist orders states can impose. You might not even be able to get liability ins if there is no proof of compliance.
* ETA; I am not sure how many states have these extra guidelines but in FL at least you cannot manufacture anything in your home. Manufacture means even decanting a product into different container. You can buy bulk cosmetics from other states, countries even, and put your label on it.