Hi Claire,
Your schedule is almost identical to ours. Yes, you are supposed to wean the BF/formula to whole milk. But their liquid requirements do reduce at the same time because milk just doesn't provide as balanced a diet as BM/formula. This is then made up in solids to make a complete balanced diet. This coincides with a slow down in their growth rate as well. You might also notice a drop in appetite (as mine went from eating like a horse, to eating like a bird around 10.5 months). They just don't need as much. Most peds will say your LO needs 16-24 oz of milk a day after 1 year. When you serve milk is up to you, but whole milk is filling, so if you serve it at a meal, they may not be hungry for solids. They also need a couple snacks during the day, about every 2 hours or so, whereas BFing is currently your "snack."
But of course, as you discovered, when making that switch to milk, they don't like it and need to develop a taste for it. Just keep offering, and round out the missed milk in their other meals. Whole milk yogurt and cheese are comparable substitutions in calcium, protein, and fat.
We dropped the bedtime feed since this was his least interested. I bought a new sippy cup especially for milk so he would understand that it's not water. I also specifically name it and make the sign (as opposed to the water sign). He really understands that it's different now. I've given him a dairy serving earlier and since I'm still BFing 2x, he should be fine if he doesn't drink it. I just keep offering it though. I also pushed dinner back, so I wouldn't have to give him a snack if he didn't drink it as well. He's never starving for dinner anyways, so I just give a cracker to tide him over. Maybe you could move lunch back, in case she doesn't drink the milk later. At the suggestion of some other ladies, I started offering only milk at dinner as well. He's had water all day up until dinnertime, so I know he's not gonna be dehydrated, but if he's parched, it kinda forces him to get used to the milk. He drinks a minimal amount at dinner the last few nights, but then started to drink more afterward. Last night he took 4 oz before bed! I also give him one last sip of water before bed, in case he's still thirsty between dinner and not drinking enough milk, KWIM? Once he's drinking the milk well, I'll probably go back to giving water at dinnertime.
HTH!