The cherry blossom bag is so cute! I also laughed at the in-between sushi!
The mini messenger is also clever--recycled stuff is just so popular now..I would make sure that you put on a tag stating that it is recycled...I attach a little card to all of my recycled goods...people like to read about what you made the item from!
I think they would be cute with those big button and cord closings...I see that a lot on stuff my young nieces carry...you would need to make the flap a bit smaller...or, maybe you could fashion something from the belt loops of the pants or make belt loops...a belt loop and a toggle type button?
You can also use belt loops as loops to attach the shoulder strap to...or for a key chain holder...or to hold a pen...you can use the zipper in the lining to make a pouch..cut around the zipper leaving some of the pant fabric...