You've missed out 'four-stroke auxiliary power unit'; the Lancaster was started up by first powering up a twin-cylinder air-cooled motor derived from a pre-war Triumph motorcycle engine; although I guess you might include this in 1?
An example of 4. First WW2 aircraft I ever saw close-up was the dear ol' Fairey Swordfish, back in 1959. Dad had taken me to HMS
Daedulus at Lee-on-Solent to see the trials of the first hovercraft, the SRN-1 - "new technology, son" - but I was much more interested in the old biplane near the perimeter fence. Two sweating mechs in overalls were facing each other on the port side and turning a handle. One called "let her go, Jack!", the pilot did the necessary, a wheezing noise was rapidly followed by a puff of smoke from the exhaust and the engine burst into life.
"What's that aeroplane, Dad?"
"Old technology, son. Hard to start, but she's an amazing sight, eh?"
Too right. The Stringbag will always remain my favourite aircraft: slow, cold, ugly as sin, the original 'Pusser's Nightmare' - but maintained and flown by hardy souls in weather conditions often so bad even the seagulls were walking.