1st/ -
What effect does this have on induction ie Do we need bigger carbs? Do we need bigger plenums?, do we need bigger valves? than as for the std stroke engine?
Since the engine is now larger in it's total C.I.D. and because of the longer stroke, the draw on the carb through the intake is longer in duration time only shortened by the cams timing events. This longer draw time can create alot of velocity to your bennifit.
Bigger carb?
Maybe, it's a combo dependent thing. You could run a 600 cfm carb on a 400 inch stroker just as you could run a 600 cfm carb on a 400 low deck big block. But this is also combo dependent just as the rest of the question like plenums and valves. The real question to any engine build is what are you doing with the engine, it's intended purpose?
2nd -
Again - Why? Also,
What causes a choppy idle and why does a stroker smooth it out?
A cams timing events will give the choppy idle. The centerline of the cam and it's overlap (The amount) play a part in this. A larger engine can use more cam without adverse effects that the smaller engine gets with the more race like cams.
3rd - Ignition timing - .
Why?
You can reduce your ignition timing on a standard stoke engine with detonation resistant ideas built into the engine and coatings on the piston and heads.
For example;
A tight quench zero deck piston with a heat resistant coating on top, closed chambered head also coated in the chamber, with a wider centerline cam (110 - 112) and reduced overlap cam will require less timing and be more ping resistant.
If you take this combo and decide to take it to the track for race purpose's, you can take this tight queezze engine and give it a ratherly large cam and still run it on the street. A race cam with a C-line of 110 - 108 would work well.
A reduction in head cc for a very high ratio over 11.5-1 is possible and would like to see a cam with a 108 or less centerline. This would be a very powerful type of cam long in duration and high in lift needing a big stall and steep gears for max performance type build but still get away with less timing than an open headed combo with a as cast/forged piston un preped with ruff edges, wrong size gasket, untouched head chamber, etc........