re: What's wrong with my satsuma tree?

Pic 1 &2 = Leaf miner. Not much you can do about it. Best to NOT spray insecticide. Leaf miners are inside of the leaves and the poison won't get to them. Leaf miners have lots of natural enemies that will eventually keep them in check, but if you spray poison, you'll eliminate the bugs that kill/eat leaf miners.

Pic 3 = Not a fricking clue. Probably some kind of fungus, scale, or other microcritter. Remove a leaf and put in a clear ziplock bag. Take to a reputable nursery or extension office for advice if you don't get a solid answer on the OB.