For the Hardie/blocks, use Tapcon fasteners and Tapcon bits. The box of fasteners will tell you the size of bit to buy. You can use the same Tapcon bit in the Hardie over the wood, but don't drill into the wood with it. You can use exterior grade wood screws for that application. I didn't mention sizes because you didn't indicate whether you were running 1/2" or 2" conduit. Generally 1/8" fasteners will suffice. Use Hex head Tapcons for ease of installation.