I'd recommend the do88 intercooler over the elevate, it flows better and pretty sure it's cheaper.
Same with the intake pipe, the do88 or Snabb is way better than the elevate.
If you were going to get the Elevate plenum, it's just a rebranded part that you can get locally, eg I think the one DVS sells is the same. But if you want a proper upgrade the Anembo one is the way to go.
Also you probably already know but I'm pretty sure the rear suspension on a C70 is different compared to an XR5/C30/S40 etc, it might affect how you can do the AWD swap.
Again you probably already know but I'm pretty sure the Bilstein B14 kit won't fit with an AWD setup, I believe you can get an AWD version of the B16 though.
For the front control arms I'd highly recommend the Whiteline KCA428, well worth it.
Looks like a nice build though, is the C70 auto or manual?