None of those are necessary but it is probably advisable to form a corporation
of some type if you are in danger of lawsuits. An LLC is one type of corporation and usually used in smaller businesses. You can even have more than one corporation to provide extra protection so that you are absolutely safe but to know if this is justified you need to meet with a lawyer in person and go over the information in detail.
There is no need to have a lawyer on retainer, that is actually fairly rare.
There is also no need for a business license for a blog.
Thank you for allowing me to assist you. As you know, we work on the honor system here and cannot always provide you answers that you like but I believe I have answered all of the questions you asked.
I believe in giving information that is to the point, but please remember that I can only base our answers on the information you provide and sometimes a misunderstanding as to what you are looking for or already know occurs so feel free to ask additional questions or for clarifications. Be very careful about looking at other internet sites that just post generic information without any inquiry into your facts because often those answers are dated, wrong, or wrong as applied to your facts. Please be aware that my answer is not legal advice, it is merely information. You should always contact a local attorney for legal advice.
Several customers have asked how they direct a question to me in particular. If you specifically want me to provide information for you just put “FOR JD 1992” in the subject line and I will pick up the next time I am online.