(2) extending 09L/27R to operate it as two rwys - this involves the ending of segregated mode and alternation and is therefore a non-starter;
(3) the "north west" rwy option proposed by Heathrow management.
If ending segregated mode is a show-stopper, then that would also apply to the NW runway option.
Communities under the current 09L and 27R approaches would lose any alternation respite and those under the current 09R/27L approaches, 50% of theirs.