Can you use 215 60r16 instead 205 55R16?
Yes, that smaller size should work and yes, your speedo will read a bit higher than it should due to the smaller diameter of the tires.
Are 205 55R16 and 205 60r16 interchangeable?
Yes it will be completely fine, in fact 205/55/16 are the most common 16″ tires.
Will 215 60r16 fit on 215 55R16?
You would have 10.75mm of extra rubber on top and bottom, which would make each tire 21.5mm taller overall, which comes out to about 0.85 inches. So – yes they will fit on your wheels. I do not know if they would fit in the wheel wells without scrubbing, but my guess is that there’s a good chance they would fit.