How many Visas allowed per household in the UK?

I wanted to know how many Visas are allowed per household in England. My family and I are thinking of moving there within a few years. My dad has found some great job opportunities in both England and Ireland. I know my dad can get a Work Visa, but is my mother or myself allowed one as well while living in the same house? I know I can qualify for a Student Visa or even a Ancestry Entry Visa, but does that mean I have to live outside my parents home? My mother will also need to work while we live there, especially with college expense, can she qualify for a Visa?
And if we can't qualify for a Visa, how many years will it take for my mother and I to get one?

I am an American expatriate living in England and I have several friends whose parents both have visas. there is no limit to how many visa a family can hold. Automatically as dependents of you father you and you mother can dependency visas allowing you to enter the country- this is all you will need if you plan on living in your parents home while going to school- however you mom would then need to apply for her own work visa, unless she gets a job with the embassy. I am told that a second work visa is not hard to come by