OP, it is great that you are trying to understand the lay of the land of college admissions at this early stage.
Someone suggested making a Common App practice account for yourself - this is a great idea. I (parent) have a practice account and have found it very helpful over the course of college admissions seasons for my multiple kids.
Another aspect you might take a peek at is the Slate platform that most college admission offices use to read applications. This will be the same no matter what application platform the student used to submit their information. I don’t have a link handy - maybe someone else does - but if you google Slate reader, or slate college admissions, etc., you will find examples, particularly on YouTube. There isn’t going to be a faster response from using a college’s own app. It is all going to Slate anyway.
Notice that Slate is owned by Technolutions, which also tracks clicks on links in college email spam to track interest. Please do not underestimate the level of data collection, and tech in general, involved in college admissions. Everything that can be automated is automated, aggregated, computed. There are algorithms, mathematical modeling to predict yield. The level of data use in college admissions is intense.
This isn’t anything like olden times when we typed apps on colored paper and then struggled to find the right color to cover typos we made with an electric typewriter.
I would encourage you to look closely at your source of information that it is better, either for demonstrated interest or for a faster response, to apply using a college’s own application. Strong suggestion: if you end up verifying this tip for some particular school, please come back to update the thread, and then for all the other schools on your kids’ lists where this isn’t true, allow them to apply via Common App.
I had twins apply to college too; you want to use Common App whenever there is no disadvantage to doing so (which, I predict, is all the colleges on your kids’ list that take Common App). You are the proofreader; ideally, all apps should be printed on paper and reviewed by hand for typos.