Yeah, a fifteen-fret uke will have two octaves. The lowest note is middle C. Then the E string (open) is the E above middle C, the A (also open) is the A above middle C, then fifteen frets down you have the second C above middle C. That's two octaves.
Yes, peanuts and peanut butter can aggravate arthritis. I was a peanut butter eater all my life, I am now 58.
The downside of boiled peanuts is that they contain fewer nutrients. In the boiling process, peanuts lose about half of their vitamin E, magnesium, folate and niacin content, as well as two-thirds of their potassium. So if you aren't watching calories or fat intake, roasted peanuts are your better nutritional bet.