You need to find yourself an architect.They will draw up your plans and tell you what you can do with regards to building regs.And the answer to your 2nd question is almost definetly no.In response to your revised question,why not give your local building control a call.Whilst building regs should be the same everywhere,i can state for a fact that some are different to each other.I have had jobs 1 mile apart (but have been under different councils) and they have totally contradicted each other.Call yours and you will know for sure!

You need architectural services, such as our selves to draw it up for you. In regards to the toilet issue, this is building regulations matter and our team will introduce building regulation drawings to comply.

The answer to your second question is a no no...

I can add to this by saying the advice on a toilet accessed off a kitchen is correct. You will need a washbasin. You won't however need an extract fan if the room has an external opening window. There is no need for a lobby (two door protection) just a single door between the toilet and washbasin area and the kitchen is enough.

You can have a toilet off the kitchen provided the toilet has a basin in the same room. You would also need an extractor fan to comply with Building Regs as you correctly said. This is contained in section 4.10 of part G of the regulations. http://www.planningportal.gov.uk/uploads/br/100312_app_doc_G_2010.pdf