Depending on what methods you used for sleep training you could drop that night feed cold turkey and comfort her through the difficulty and frustration she will have. Or you could do a rapid wean (that would be my choice, I am not a cold turkey fan myself) where you reduce what you offer each night:
night 1 50ml
night 2 40ml
night 3 30 ml
night 4 20 ml
night 5 and there after water only
Nights 1-4 I would take an additional bottle of water, if she is not happy with the amount of milk offered then offer the water but that's all she has, you don't go and get more milk. After night 5 I'd expect her to not wake for the feed but if she did you would offer only water and help her back to sleep. If the NWs continued I'd try a W2S to see if you can cut the NW.
An 18 month old really doesn't need the night feed (unless very very poorly and has lost weight due to illness and is trying to catch up on missed calories). It sounds more like a habit/prop than a need to eat if she is only taking 60ml.
If she's teething and in pain during the day putting her off her food she might like some additional milk in the day or some different foods which are more comfortable to eat - these could be softer, colder, or even harder. Mine liked hard bread sticks during teething, it gives something to gum on which actually reduces the pain in the gum.
hope this helps
