Getting an new A1200 is no bad idea, but also take a look at the new Amiga One, if you haven't already.
Yes, there is different versions for PAL and for NTSC.
You may use VGA without any problem on an standard PC VGA monitor, all that is needed is an adapter, as the connections are not the same. No flicker fixer or scandoubler is needed.
But if you want to make use of the SVGA resolutions then a flicker fixer is recommended, to avoid the flicker.
Also the standard HiRes Laced is faster than VGA modes, so using a scandoubler wiht flicker fixer could be an idea even here. And if you are going to play games and demos, well then a scan doubler is needed if you are not to use the 1084 or a TV set.
It's possible to find flicker fixers for the A1200, but they cost as much as the A1200 itself, maybe better then to think about a solution with a PCI graphic card, well even more expensive but also better.
I think, the mother board revision is not that important, but if you may find an A1200 with kickstart 3.1 that is of course better.