I tend to post multiple videos on weekends because I normally edit multiple videos at a time over the period of a week late at night when the rest of the family is asleep. It is hard to imagine that you could be posting high quality content and have the ability to produce multiple videos from shooting to editing in one single day. For instance, DCTC (a big toy channel out of NC) has a commercial studio with paid professionals that help edit the videos and they were on the news saying that they each work over 12 hours a day to produce a video.
With kid channels I would not worry about multiple uploads per day. Even a channel with a 100,000 or more subscribers get the majority of their views from non-subscribers through suggested video. You may get some older kids to remain loyal to your brand from a subscriber point of view, but the majority of views come from the algorithm of suggested video that obviously factors in channel authority and overall watch time. The kid channel market is over saturated and very difficult to become successful. It is also difficult to understand because a lot of people watch a big channel with millions of views and the content is terrible, the audio is bad, camera focus is bad, and it is pretty much bad content with the exception of a thumbnail that looks nothing like the video. So you think I can do better than that. Well, the problem is those channels are big and they can post a video of them eating a piece of corn and it will outperform your video 99.99% of the time.
For instance, Hobbykidstv has released three videos within the last 22 hours. They have 1.6 million subscribers and some of their videos over a week old have less than 20,000 views. It is obvious their strategy is mass produce at the sacrifice of quality. They live off channel authority and suggested video waiting for the viral hit which they get quite often. I would not be surprised if their average watch time is under a minute, but they have a billion views. Youtube could obviously work it out to penalize this, but obviously they don't. Hobbykidstv is very successful and rich, rich from a monetary standpoint that is.