Originally Posted by jiejie

It's been done before but using two additional real passports (not scans) of family members not traveling, to purchase and pick up the tickets. You might succeed with using two additional scans and you might not. Scenario 1 above is very possible. Scenario 2 is possible if the conductor calls your bluff and demands to see 4 real passports to check against the tickets (and/or wants to see 2 more real furriners show up!).

IMO, it's your gamble but if you're not willing to suck it up and share with two other people in case you fail, you shouldn't be taking this form of transport, at least not for this long. There's an outside chance that on a daytime train, the other sleepers won't even be sold or won't be sold for the entire journey even if you don't try to buy them, especially in soft sleeper. If you only buy two sleepers, tell the agent you want lower berths in one compartment. They can do this if they wait for the 18-day advance sales period and request from a ticketing office rather than book online at the 20-day advance period (where berths are assigned sequentially and you will almost certainly get a lower + upper.)

While I don't know the context of your travel immediately before and after this segment, I'm not convinced that this long train ride is your only (or best) option. Are you visiting Fenghuang or just wanting to get from Zhangjiajie/Wulingyuan to Guilin as quickly as possible? Are you going to the Longji Rice Terraces or omitting?