I think the 2017+ 650's are fairly similar, if not, ignore me:
Mine slid straight off, no problems at all. The worst pipes were the two rubber ones (they were
only just long enough to put back on), and the clamps did not fill me with confidence as they just seemed to slip over the barb... IMO I wouldn't put any grease on these.
My fuel pipe just came off mine once unlocking the connector - you have to make sure it's fully unlocked as mine partially unlocked, seemed to move, but then jammed up. Once fully unlocked, it came right off. I'm not fully sure on the internals of the fuel pipe connector, if there are internal o-rings/seals then a very small amount of silicone spray on the tank side might help with reassembly, but let others comment their ideas first before doing this