I'm sorry if are not getting the sympathy you expected.....
Most of the issues I'm seeing are on you, not the tenant. You need to start running this as a business.
Late rent is totally your fault. You have allowed them to get away with paying late and they are abusing it. Rent is due by the 5th, pay our written quit notice go out by the 7th, by the 15th we have started eviction process in court. In Texas you can have a court judgement before the end of the month.
I can't believe you are allowing a non-approved home business. You should have sent notice the minute you found out. Not only is this illegal, it is a huge liability for you as the property owner. Imagine if someone gets sick or injured. Any smart lawyer is going to come after you as the home owner. Your property insurance is not going to cover you either. I'm sure there is a "home business" exclusion in your policy unless you purchased a special policy. Not only that but I doubt the tenant has the appropriate business licensing and health inspections. Home business is grounds for eviction.
Sorry, but you are in over your head. You need to seek the advice of a professional property manager to unravel this mess.