Hi Jen, welcome!
All i can say is, I gave up on extending, as you can tell if you read this whole thread. It simply wasn't working. If he's really OT I accidental parent him until the OT goes away (rocking or swing, usually). How quiet is your pump? Can you kill 2 birds with one stone by pumping while you shh-pat her back to sleep?
Right now he's going 3.5-4 hours between feeds, so we're sort of going EASAS, EASAS, EASAS. The annoying thing is DS still needs a full 15-20 minutes of help to go to sleep, then only naps for 35-55 mins. I spend a lot of time in his room! When I find the key I will share it with you!!