Not usually. You only need the alignment tool if you remove the clutch plate from the flywheel. But if you're a bit ham-fisted and unlucky when separating the engine from the gearbox it's possible (but not easy) to knock the plate out of alignment, in which case you'll need to loosen the clutch cover set screws to allow the plate to be re-aligned and then re-tighten the screws. The correct tool is best (the one which comes with the Valeo kit is a simple blow-moulded bit of plastic and does the job just fine), but in the past I've used thick wooden dowelling or even just carefully measured all round to ensure concentricity. I've also played my luck and aligned visually on some cars, but it's not something to be done by choice as it's easy to misjudge.

Clutch alignment is to ensure that the hole in the middle of the clutch plate into which the gearbox input shaft locates is located dead-central. If it isn't, you can't fit the gearbox back on. Don't forget to clean the input shaft splines and then smear a very small amount of Copperslip grease onto them before reassembly, too little is far better than too much.

self-ejected the engine onto the road surface in a matter of seconds..

Easier than a dyane, I think.

Best thing to use for an alignment tool is an old input shaft from a scrap gearbox.