The data is wrong for both aircrafts. According to Airbus, the standard A350-900 can carry 138,000 litres of fuel. Wikipedia lists a maximum fuel capacity of 126,000 litres for the 787-9.

In the worst case scenario (all the fuel is needed and the cargo hold is empty), we are looking at a 3.67 litres/100 Passenger-kilometres for the 787-9 and 4 litres/100 Passenger-kilometres.

That said, the calculation does not take into consideration freight. Moreover, Lufthansa reported an average of 4L/ 100 Passenger-kilometres in 2012. IIRC they advertised the A380 with a consumption of 3 litres per passenger and per 100 kilometres.

I expect a long-haul 787/A350 flight to be somewhere over 2L/100km & passenger.