I just recently gave a neighbor kid an Arvista, from what I can tell it will be a great trainer.
A hole between 2 ribs? If you are not overly concerened with looks just cover it with clear packing tape. If you are you can get self adhesive Monocoat and put that on or even a decal if you have one laying around.
By driver for the MDS are you refering to the Prop Hub?