2 - convert to an alternator, and add an extra wire if you get a powerful one. Instruction readily available if needed.
4 - get silicone hoses if you can afford them, avoid Kevlar ones
7 - look for a mk4 air box if you want cold feed, readily available
9 - float is full of fuel or the sender is jammed, empty the tank and pop it out.
11 - some modern pads are rubbish, if not worse. Cardboard or wood is probably better!
14. - the column is adjustable on a Mk3 so perhaps try that first.
16 - try door mirrors if you think you need, the wing mirrors are rubbish on Spitfires
18 - the hood looks a good fit to me, can you get a better pictur?
also, you are missing the correct breather assembly, I wonder if the inlet manifold is a Mk4 one.
cheers
colin