Does the Brit rail pass include sleeper cars?
John, I don't know about British railways specifically, but Sleeper or Couchette costs are rarely / never included in the cost of a Railpass. You'll likely have to pay separately for that.
John - Where are you looking to take the sleeper to? For information on the Caledonian Sleeper check out www.scotrail.co.uk
Edinburgh to Brighton. Mid-week.
As you can see on the link provided there are no sleepers to Brighton. They go from Scotland into London Euston. From Euston you can go to St Pancras Kings Cross down the road and take the First Capital Connect slow train to Brighton, or the Victoria Line Underground to London Victoria and the Sothern Railway fast train from Victoria to Brighton. The easiest way is the day train from Edinburgh by East Coast to Kings Cross, then downstairs to the First Capital Connect to Brighton.