Hi,
Yes, I think 74hc4051 should be suitable. You will need at least 2, which will give you 16 analog inputs at the cost of 2 Arduino analog inputs. You will then have 14 remaining Arduino analog inputs, giving 30 in total. You will need to connect 3 Ardino digital outputs to the chips to select the channel, but both chips can share the same 3 digital outputs.
Yes, you can measure all 30 channels every second, or any other sequence you need.
Paul