I am right there with you. DS5 turned 5 in summer as well. He too attended PreK last year. We did most of the homeschooling when DS5 was in PreK and it worked quite well. How old is your older one? Mine just turned 7. I am still getting used to typing DS7

My main worry is how to keep DS5 busy while giving enough attention to DS7 when he needs it. DS7 and I are both used to the one-on-one situation we enjoyed last year. It will be hard to leave it behind. DS5 and DS7 have different personalities. What worked for DS7 may not work for DS5.
My oldest is 8, would be 3rd grader if he were in school. I know what you mean about the differing personalities. My daughter pushes both mine and her older brother's buttons often! I joke she may be in a kindergarten classroom by October if she doesn't watch it!
On the bright side, given the right art supplies she will occupy herself for a LONG time. She's ahead of the curve, but I don't really have a good feel for her yet. She's also 9 months younger than DS was starting kindergarten. She's ahead of him in some things behind in others. We'll see!
Back to that happy state of denial!