Hi. For picks, I would get a few different ones and decide which feels best for you. I personally preferred a lighter pick at the beginning and then settled on a medium after I got better form. (Think it's a point 6 or something; the numbers are worn off.) If I go to heavy a pick, I find it "grabs" the strings too hard. I need something that flexes a fair amount.

lol on the strap! :)

You might be whacking your E string too hard making the buzz. Especially open, A & E vibrate a lot more then the rest. You can see it visually the blur when it's vibrating is pretty wide. Otherwise some new guitars can use a little tweaking on the set up, such as raising the bridge. Probably best handled by a professional.