If you have 16 notes on a 4/4 time signature, then they are all 16th notes as you said. They are in 4 groups of 4, so the first one of each group would be the quarter note.

1e&a 2e&a 3e&a 4e&a

As for tempo, let me try to figure that out and Ill edit it back in. After 11 years of playing guitar I'm just now trying to learn how to read music since I'm picking up drums now, so this is a good challenge for me :)

Edit: Alright, at 60 bpm, each quarter note (the first note in each grouping) will be each second. You would play all of your notes at a constant speed. I'm not sure if thats what were you were asking though. Kind of hard to describe time in words, but Ill do my best lol:

1...e...&...a...2...e...&...a...3...e...&...a...4...e...&...a
1second........2s ...............3s...............4s