Best advice: Be honest and Fair
PVPA and Copyright - Before growing a variety, look it up. If it has a PVPA or copyright, then contact the owner and ask permission. Frankly, I am not bright enough to work with contracts so I ignore variety like that. On copyright, you can look up the copyright and see what the rules are. Example: Smoken Ed's Carolina Reaper is protected, but the copyright says Carolina Reaper is not. So folk sell Carolina Reaper instead of dealing with what ever rules Smoken Ed has for using his name. Its all good.
Exit Rules: Puckerbutt and some others have a list of rules as you exit / purchase. Most people dont read those sort of things. You should read them and be honest. Puckerbutt says no commercial use of their seed stock, so I dont buy from Puckerbutt. Its nothing against them. I just want to be honest. Even if I purchase for my own personal use, since I am in business I might give the wrong impression.
What I said in PM about check with your extension office and how much is state by state means I cant really help with details because I am not in your state. But a couple other things came to mind.
Sales Tax - Kentucky does not collect sales tax on food or seed for growing food. Your state might be different. You might need a sales tax license. We have one, but mainly because I sell hand made knives and metal work. Because I have the license, they send me a form every three months. I fill it out and mail in a check. Again, nothing but a thing. Very easy. I live with brain damage and I can do the math. You will do fine.
DBA - Unless you sell under your own name, many states require you to obtain a Doing Business As sort of thing. Again, nothing but a thing. It actually protects you because nobody else will be able to get a DBA in your state under your name.
General Business License - Now this is a weird one. Some states want you to have an actual Business License even if you are not collecting sales tax.
LLC - Not required, but a good idea. Again, this is nothing but a thing. Dont let it scare you off. In my state, once you get it all you have to do is fill out a post card once a year saying it still exists. Lets you get a checking account in the name of your business. Other than that, well it is good as a form of legal protection of your personal assets.
For this and other goofy legal stuff, contact the Small Business Association. For anything specific to your product, contact the local extension office. If you have something like SCORE in your area use them. Google something like SCORE and small business to see who they are.
Biggest thing to remember, dont let any of this scare you. It sounds really intimidating, but its nothing but a thing until you get big time and have to deal with the federal laws. For now, you have exemptions. By the time you are earning enough to be stuck with the federal laws, well you will be bright enough to realize even those are nothing but a thing.
You will do GREAT and anything I can do to help just ask.