You are running into two syntax difficulties with HDL.
First, you cannot connect a pin named in an OUT statement to any input. Second, you cannot use the sub-bus syntax on internal wires.
What you need to do is make the 8-bit buses you need for the Or8Ways in the same part where you connect to the ALU's out:
Something16(..., out=out, out[0..7]= ...);
Study the example in appendix A.5.3 to see how multiple connections to bus input and output pins works.
(This will make 'ng' easier, too.)