I would cut out the noon meal now-I usually do it around 6 months.
Technically a dog can be on puppy food forever. All Life Stages foods are the same AAFCO profile as a puppy food, and I tend to like them more in general. Just make sure you are feeding the appropriate calorie intake based on her age and size.
Rotating toppers is fine, I start a rotational diet of toppers and kibble as quickly as possible. With Dani, I bought 2 small bags of what the breeder had her on, and fed the first one, mixed the second, and moved on to rotations right after that, and worked out great.
As far as what is appropriate to top with, if it isn’t a balanced meal (like THK which is, but I usually reduce the amount of dry accordingly with that) like chicken or fruit/veggies, just try to make sure to stay under 20% of total calorie intake as unbalanced toppers. I rarely feed unbalanced toppers because I do so much training, that I count that in for calories as well
