You need to consult with a trademark attorney, providing the information which you are not providing here -- i.e. identify the 2 trademarks, explain what your business does, explain what you believe the other company does, etc. The trademark attorney may be able to give you an opinion on the spot, or the attorney may need to obtain a trademark search (out of pocket disbursement ~ $700) and evaluate it.
You are asking a lot of questions, and providing zero information from which the answers to any of the questions might be determined.
These are complex questions, because usually the band members don't enter into written agreements which would have made them simple questions.
All you can do is go to an experienced attorney like myself, explain the facts as best you can, provide whatever documents there are, and start working with the attorney to try to take an assertive position.
It's a very complex area of the law. It's on a case by case basis. There is no way to give an opinion except upon a very specific set of facts, and even then it's often difficult to say with any degree of certainty if a use is a fair use or not.
I would love to see regulations or statutes which spell it out more clearly, but there aren't any.
The heading of your question is quite misleading. The real question you are asking is quite different.
Assuming the works are copyrighted works which have not gone into the public domain:
You are free to sell the vinyl LP's.
You are not free to make "backup" copies of them.
You are not free to sell "backup" copies of them.
If you pled guilty to a misdemeanor, I don't see how you can sue someone for having said you did the thing to which you pled guilty. As to whether you have a case against the company, you would need to consult with a lawyer, giving all the facts. I don't see any point in your bringing such a case without legal representation.
It's not necessarily so clear, but the way to make it clear would be to enter into a written agreement that the photographs were "works for hire" and that you are the owner of the copyrights in the photographs. If the photographer signs, fine. If not, then the situation remains murky.
Correct that a record "label" is not necessarily a company, but a brand. The same company may have more than one label. However, if you don't have a company, and your business will be acting as one or more record labels, you should set up a corporation or llc.