I've had this open all day to reply. I can so relate to feeling touched out over night. DS still fed 6ish times a night for a really long time.
I tried a few times with DS too. He was well over 18months, closer to 2 I think when he finally accepted a drink of water as a replacement. Catch 22 though because I gave him a bottle....now I can't get rid of it overnight. He was drinking 750ml+ of water overnight, so obviously he was thirsty. He's cut back to 300 now but he still wakes and asks for it.