My 89 kili flyer comp is 27.0 seat post - based on what you say for the 27.2 I'd get a cheapo 27.0 one (think I got a kalloy one for a fiver.....). If there is no saddle also then you can pick up those modern reproduction Selle Italia turbo saddles quite cheaply (sub £30) - they suit this bike very nicely.
In terms of gears some people on here will say stick to the original 3x7 but I'm more open minded. I think 1x1 is cool if it has horizontal drop outs or you have the patience / skills to find the magic ratio. The chain tensioner will spoil the look. I think 1x7/8 is also good - although if the rear spacing is 130mm just check the freehub can take an 8 speed cassette.
In terms of gears some people on here will say stick to the original 3x7 but I'm more open minded. I think 1x1 is cool if it has horizontal drop outs or you have the patience / skills to find the magic ratio. The chain tensioner will spoil the look. I think 1x7/8 is also good - although if the rear spacing is 130mm just check the freehub can take an 8 speed cassette.