To understand who "owns" the KHs in the US at least, is to understand the laws regarding non-profit corporations.
http://definitions.uslegal.com/n/non-profit-corporation/
only when a congregation is dissolved, does the "ownership" revert to the parent non-profit corporation the WTS.
BTW only the congregation that holds the territory in which the KH building sits, forms this non-profit corporation and only elders from that congregation are trustees. So if East, West, and North share a KH but the KH building is in North's territory, only the North congregation forms this non-profit corporation.