My DD2 is 6months old and was drinking 5 bottles a day, and around the same as your 6month old with the solids. I also would wake her for her last feed. With what you are considering doing I did and she didn't wake up, but after a few weeks when I didn't wake her she started waking around 3 in the morning looking for a feed. All children go through different stages of growth spurts and wanting more or less, my daughter goes weeks being content with having 4 bottles then changes to wanting 5 bottles for a couple of weeks.
If you drop the last bottle that you wake her on,expect the possibility that she may wake up. Don't worry about safely dropping the late bottle without making her hungry, trust me if she is hungry she will wake smile
My DD2 isn't that interested in solids as was my DD1 so each day I have been offering her more solids even toast and bananas, obviously watching her at all times and then rice cereal, and then dinner.
You will just have to try it and see what happens, trust your own instincts as her mum, you will know what works for you and for her smile