If you both have metal lines, then maybe that is makin the noise go bwteen the houses.
It could be their faucet has noise in it.
In the clunk in the meddle of the night, mybe its the ice machain in thar fillin up. Or it coud be the tartlet filinn. Check the flapper on thet one. and maybe e'ts it.
If its the ice filler, then get a hammer device and that will stop it.