If a deal goes against Chinese interests, it probably won’t happen. And any deal that does happen would probably improve China-North Korea relations.
South Korea has lived with a serious North Korean threat for 65 years. Moon is driving this diplomacy, and he, like previous pro-engagement presidents, believes increased North-South interactions play to the South’s advantage. It’s safe to say South Korea is not demanding complete, verifiable disarmament as a requirement for any agreement.
Fair point on the Russia omission. However, while I wouldn’t say North Korea-Russia relations are “trivial,” they’re less important than North Korea’s relations with South Korea, China, or the United States.