Why does she still wake 5x a night?

Put her in own room, quit feeding her at night. If she knows she isn't going to get a bottle then she'll quit waking up for it. You can quit cold turkey, or put water in it instead of milk, or decrease the amount in the bottle each night til she decides it's not worth waking up for. She definitely does not need to be eating in the middle of the night for nutritional reasons at 15 months. It might be rough for a few nights, but it'll be worth it when she's sleeping all night every night.