Hi mimi!
We moved from breast to bottle when DS was the same age as your LO and we were finished with BF when he was around 10 weeks.
What I did is replacing the feeds that were more "inconvenient" for me, but not too close to other feeds. So like you we had one feed in the middle of the day changed, then the BT feed, another feed at night and slowly we changed the rest. What I did find, and I think this is what's happening with you, that the transition was quicker than I wished for (I wanted to continue combining for a long time) because my milk supply went down drastically. I think that if you want to prevent that from happening and continue with the BF then you need to pump for a while.
For us it was just one day - DS just refused the breast and wanted only bottle.
And like with your LO, he could not go very long between feeds, even when he was fully on formula. Like Laura said, some babies take a while till they can manage longer stretches between feeds.
The faster teat can take a few feeds till they start throwing up so I would give it a try for a day or two before you decide if it's working or not.
I thought that DS will never get to 3h between feeds, but I can tell he did! And if it happened to us it will happen to you as well, just might take a while longer than other babies.
The NW or if there are difficulties with naps can be because of her routine, maybe something needs tweaking? It's not necessarily that she wakes up for food at night. If you want you can post your day in an EASY format and we can have a look at it
.
Hope that helps
.