I imagine the A350 will look very similar to the A330. Length may vary, and maybe new engines. But if what I have read is correct

then it'll look very much like an A330.
The 787 is an unusual design in my opinion, in detail, rather then overall layout. Some of the cockpit window shapes that have been illustrated or modeled are certainly 'different' and that tailfin looks odd! I almost expect it to be in the middle, like a shark's!! But that owuld of course make it useless, aerodynamically!