Topic: Trading Name vs Business Name - Legal and Financial implications for more than one 'business'

CONTEXT
I intend to start two unique businesses:
1. An online retail based company
2. A service based company (IT and office oriented)

1 and 2 require different 'NAMES' for branding purposes (definitely two different websites - they need to be unique)

Questions:
1. Do I need to register both names as businesses (and therefore provide different sets of accounts for each)
2. Do I need a different bank account for each
3. Do I need a different set of accounts for each
4. Can I use my PERSONAL bank account and VISA card for company purchases as a sole proprietor

My sincere thanks for any help you can provide!!