Being a single person LLC absolutely does gives you the legal advantages of an LLC, provided you maintain separation of personal and business, eg keeping business bank accounts and routing all income and expenses through them, keeping proper accounting books, signing contracts as the LLC and not as yourself, holding company meetings w/ minutes, etc.
In practice this protection isn’t worth as much as it is for larger businesses because, for example, any bank lending to a new single person LLC will require a personal guarantee anyway, and most single person LLC don’t have a lot of situations where they might incur a life destroying liability, like an accident in a warehouse or something, but that protection still definitely exists for single person LLCs.
Write down your plans, decisions, and reflections. It's something you should probably be doing anyway.
The only silly part is calling it a meeting, but people do seem to agree that's the terminology the IRS wants to see.
Actually, I guess there are two silly parts, although the second is arguably more sad than silly: you must be 100% clear that you are engaging in these activities with a profit motive and not for the love of learning, doing, helping... and if the IRS decides that your motive is not sufficiently (im)pure, you will owe considerable back taxes, interest, and fees.
Haha it is rather ridiculous, but you can formalize big company decisions in a sort of company secretary’s binder. Honestly though, keeping the finances and contracts separate will basically always be enough to avoid personal liability. Basically you just want everything to be partitioned enough that no one you do business with would ever think that they are dealing with you in a purely personal capacity rather than as a representative of your company.
Generally, anyone that a company has duly authorized to sign will be able to sign on behalf of the company. I'm just guessing at what the GP meant, but I think the most important thing is to just negotiate the contract as the LLC. I suppose it makes sense to be particularly clear on the signature page that you're signing as manager/agent of the LLC.
In practice this protection isn’t worth as much as it is for larger businesses because, for example, any bank lending to a new single person LLC will require a personal guarantee anyway, and most single person LLC don’t have a lot of situations where they might incur a life destroying liability, like an accident in a warehouse or something, but that protection still definitely exists for single person LLCs.