The 787 and A350 are actually not in the same market. The 787 is a surprisingly small aircraft, even in its stretched variants. The -8 has a typical seat count of 245 (range 7350NM), the -9 280 (7635NM) and the -10 up to 310 (6430NM).
The A350 on the other hand starts with the -900 with 325 passenger (8100NM), and the -1000 around 365 (8000NM). The -900ULR usually has a somewhat lower seat count to achieve the proposed range, current operators have them configured with 170 to 250 seats (up to 9700NM). All seat numbers except for the ULR are typical three class layouts, the ULR often has mostly business seats and not much else.