I did have to invent a one-to-many fan-out part, as I see no (allowed) way to wire up a signal to a bus input, and there is no trace (wire) primitive, which seems a bit odd....(pun intended :-P )
It sounds like you may have figured out that Xor can be a controlled inverter. I've been designing that way (And, Or and Xor bus wide signals with control signals) for way to many years to change...
I wrote a Bus16(in, out) part for the first version of my ALU. I used a Mux16 to implement Bus16 because I was too lazy to type all those s 8-(. I also wrote a Wire(in, out) for direct connections.
You can put them in your nand2tetris/tools/builtInChips directory and they'll be available for all your chips to use.