With my DS we dropped NFs at 8 months, he was a tiny baby so we waited until he was well established on solids and the NF started affecting day feeds, so we weaned gradually, reducing his bottles by an ounce every 3ish days.
With DD she literally dropped it all at once and she's now STTN. I never did a DF with her (or with DS for that matter) and one night she woke up at 11:30pm and I thought 'it's way too early for a feed' so I just resettled her and she slept until morning. And that was enough to make her increase her day feeds the next day and just kind of set her on that cycle of eating more during the day and nothing at night. For a while she was waking at midnight and it was absolutely habitual because you could time it, then the one night I just resettled her and that was it, NFs were done. It's been almost 3 weeks now.
I am wondering 2 things for you, if you stopped the DF if he would sleep until the 2:30am feed or if you kept the DF and resettled the 2:30am feed...it could be worth trying either just to see?