I am putting a sound card on my other x16 lane Will -

You can put smaller cards in a larger slot, but not the other way around So a 1x will fit in a 16x or 8x slot but a 8x won't fit in a 1x

Yes, it works just fine, obviously it's only work at x4 speed I would check whether the x16 slot can handle the power load of the

candy burst pg slot You can insert a PCIe x1 card into a PCIe x16 slot, but that card will receive less bandwidth Similarly, you can insert a PCIe x8 card into a

can you put a single coil pickup in a humbucker slot if the slot is open like that, you should be good to go if it's not open, you could a) use another riser to adapt the x8 to x16, or b