firstly, i'd buy a dc jack that you know fits in with what you need (ie. one with 3 pins) because, as you figured out, one of the pins is to disconnect the battery when a cable is inserted.
secondly - i believe the main reason for using point-to-point on perfboard is that making a layout for stripboard can be quite troublesome, so doing it point-to-point virtually eliminates any layout problems.
thirdly - you might get away with soldering the IC directly to the board, but you won't be too happy if you do fry it...they're not really a pleasure to remove. so again, find an IC socket that will actually work.
fourthly - personally i'd make my life easier with this one, and just buy some 3pdt switches (although good luck finding them in the UK - diystompboxes.com or smallbearelec.com are the best to get them from though)
anywho, enough rambling.
Dan.