If you want to build the motor for the turbo setup I think getting the used block is a good idea. I've actually got a couple at home in storage right now.
You should be able to find either a complete short block or stripped block for relatively cheap. Hell, you might even be able to consider upping the displacement to 1.8 while you're at it by finding a GSR or LS block. Then like stated, you can get that block built while still piecing together your kit. When it's all done and you've got all your parts you can pull the B16, put together your new motor, bolt on all the turbo parts and drop it in as a complete setup. Or you could swap the motor in, break it in without boost, and put the parts on later... There's many options, and I think you're on the right track.
I however decided to keep my original block and such so that the VIN tags would match. Not a big deal, but I like the idea in case I want to sell it down the road...