Answer to #1 - Yes, if you live in a cabled area, no if not - you have to use a standard telephone line. Thankfully this no longer has to be BT. Cable & Wireless, under the guise of Bulldog, now (I believe) offer telephone line and Broadband via telephone line.
#4 - ensure that you have up to date copies of Gas & Electricity safety inspections. Gas (CORGI) is a legal requirement, not too sure about Electrical.