Honestly, that side b is killing you. If you need to reposition, try using a combination of wavelands and dashdancing. F-tilts are your friend, and understand that it's not always a good idea to egg spam from ledge vs some characters. All around, you make really good use of your spacing, but you don't really have a solid approach. Double jump cancelled attacks are always fun, but even try changing your attacks up by doing a dashgrab. I myself picked up yoshi, and the unique thing about him is how he can travel through the air. And use that d-air more. It has really high damage potential and can usually be followed up with a jab reset into grab or an up tilt/f-tilt. Either way, just keep playing. You'll get there man.