hi there really sorry no advice but just wanted to say you are not alone - your post describes want we are battling with ! we too are at the end of our teather and dread the nights. i appologise in advance that this is a long reply!
our DS is 12 weeks old and we have always worked on a bed time routine similar to yours. he used to go down lovely at 8. for the past 5/6 weeks however he either goes to sleep for half an hour, then wakes up and crys inconsolably for an hour, or starts crying for an hour as soon as we put him down.
we've tried to rock, leave to cry for 5 mins then shush, attempt to feed, check for wind but nothing works and every night is 40mins-1hr cry, then 20 - 40mins battle of dummy in and out till he falls asleep.
he too started screaming at feeds and he has been diagnosed with a silent reflux and has been prescribed gaviscon and ranitadine, but the 7.30/8pm feed is still a battle. last night i only got an oz down him.
we too have started to think this is habitual behaviour and we are thinking about 'mixing up' the bed time routine - but are so frightened changing things might upset the rest of the night - cos once he's asleep at 1030pm he only wakes once in the night.
we don't want to delay bedtime until 930/1030pm when he tends to fall asleep incase we just delay the hour long scream up till then.
we tried feeding him downstairs - only worked for a week.
i've thought about un swaddling him but think his wriggling would wake him up.
i'm tempted to try white noise even bought a CD - we hoovered the bedroom one night which stopped the crying!
after xmas we are going to introduce a bath to the bed time routine. and might move his moses basket out of our room into the nursery thinking a change of scene might work.
i'd be really interested to hear if you manage to crack this. and what you are thinking of trying.
i'll let you know what happens with the white noise.