One of features of the publication that you have is its workable, in many ways as much as a training guide as it can be flexible to your schedule.
Notice the guide can be flexible to your needs, not the dictates of a mandatory time and place. The publication is brilliantly formatted that way and flexibility is built in to every topic.
There was considerable input and editing with what you have, and although I'm not selling, editing or authored any of it, its contents will serve you well and that of your son. Just be patient with your boy as you "feel" your way around, because it does take a bit getting use to a training style.
Just remember, that publication is there to help you, not to dictate a strict adherence to seasons as set forth by others experience.
To address you question directly, I see nothing wrong with your itinerary. It should work well for you son and compliment his swimming experience also.
Best wishes to you and your son with your baseball experiences. And please post from time to time on how your boy is doing. That's another plus with using that publication - we're all here on the same page(s) as you are.