Before I comment with a few notes of my own, here are two sections that are in the JJWXC version but not in the official translation:

During the night they're being menaced by skulls:

Danger has just passed, and the tall bamboo guy is looking for more trouble, "Professor, can I go take a few pictures... I'm not going outside, just beside the window."

Shen Wei really wants to know how this kid grew up to have such a sense of adventure.

A grabby, dirty hand comes for Shen Wei's shoulder, and Zhao Yunlan leans forward, lowering his voice, "It's not against the rules to take pictures, but you have to know: it's said that cameras can capture the souls of people. Do you want to bring a few ghosts to keep as pets?"

The bamboo guy trembles in fear after Zhao Yunlan's eerie, ghost-story-telling tone.

Zhao Yunlan smiles and continues, "I guess you could bury them in flower pots, and then whenever midnight comes they will come out and start munching at the pots, munching at your table, and munching at your bed..."

Zhao Yunlan has yet to finish, and the bamboo guy twitches in discomfort.

Shen Wei's mouth quivers, "Are you alright?"

The boy's face looks uneasy, and he stutters, "I... I... I have to pee."

So scared that he's wetting himself; Zhao Yunlan is surprised. Soon, he laughs wildly and mockingly.

"It's only three hours till sunrise." Chu Shuzhi says, "My talismans can last for five hours, don't worry... but you better wait till the sky is bright to go to toilet. If something wants to bite you, pee on it; virgin pee repels evil spirits, it might not kill them but they would probably get a brain concussion."

More of Zhao Yunlan musing about when he might have met Shen Wei before, and why he can't remember:

Before ten years of age, he didn't know anything, probably even had trouble telling men from women, so nothing could have happened then. For the periods when he was older, his memories are clear and in sequence, he remembers everything precisely.

There are indeed ways to mess with someone's memory, for instance hypnosis, or other secret techniques that Zhao Yunlan can think of. But these methods only prevent the person from recollecting the altered memories. Human experience is incredibly complex, and only that person himself can know in detail what happened.

For instance, if a guy had a car accident, when he looks back, he will realise the accident happened because he was running late. And why was he late? Because he had a stomachache and was stuck in the toilet. Why did he have a stomachache? Becayse he ate too much oily foods. And why did he eat so much? Because his fast food coupon was gonna expire...

If he keeps going, he would remember who gave him the coupon, was it from someone else or did he just get it on the streets, et cetera.

Every minute detail in someone's memory can be recalled from interconnected events. No matter how smart you are, you can't possibly figure out all the trivial details in a chain of events and alter them one by one.

If someone's memory is manipulated, these details will be obscured, and when that person tries to recollect them, it would appear unnatural.

Coincidentally, Zhao Yunlan is an expert in memory.

Since he was little he knew how fragile and crucial a person's memory is. When Da Qing handed him the Guardian Order, the first lesson was teaching him to regularly reorganise his memories through meditation. Zhao Yunlan is certain that he didn't know Shen Wei before they met.

Conversely, the brief conversation between Zhao Yunlan and Shen Wei when he asks him if he was watching him, and Shen Wei agrees to talk after they get back, isn't in the JJWXC version - there, he only thinks that he'll talk to him in the morning.

Here's the bit from the official translation (it's interspersed with the introspection that's in both versions):

Shen Wei silently came over and handed him a thick jacket. Zhao Yunlan accepted, wrapping it around himself and his cat. As Shen Wei turned to leave, Zhao Yunlan spoke, too quietly for anyone else to hear. “Earlier, were you watching me?”

Shen Wei stopped in his tracks. [...]

“We knew each other before, didn’t we?” Zhao Yunlan asked quietly. “You told me that you’d encountered me once during a case, but that wasn’t all, was it?” [...]

Shen Wei was facing the other direction. His back was so still that he seemed to have become part of the night.

Zhao Yunlan’s cigarette finally reached the end of its life. Distracted, he stubbed it out and rudely threw it out the window. It hit a jumping skull square in the forehead, and the white bone instantly turned black. The skull fell to the ground, twitched a few times, and stopped moving.

“After we get back, can we meet up to talk?” Zhao Yunlan asked.

Shen Wei said nothing for a long time. Just when Zhao Yunlan was resigning himself to not getting a response, a low voice came from the darkness. “All right.”