1. Electric Captains/Ottoman seats - no. Normal seats - yes but it's not flat so but you'll need to fill in dips with foam/fabric
2. Pointless, doesn't seem to make much difference in 99% of situations and it's another thing to go wrong
3. Anything from 18-32 MPG depending on driving conditions (i.e. no point asking as it's so varied)
4. A tad overpriced but depends on other options it has. Also, if buying from a dealer you'll have the dealer premium
5. Relatively yes, Amayama.com, local Toyota or any number of breakers around the UK. The bigger the part the more expensive shipping will be, so don't ever scratch or damage the bodywork or bumpers as you'll need to sell your kidneys, and your children's kidneys to cover the cost of shipping a bumper from Japan.