What is difference between repeated poles and distinct poles?
Distinct poles do not need to share an x or y coordinate. They are classified as distinct as long as they do not share the same x AND y space. So any two poles are either distinct or repeated.

The effect repeated poles have on the impulse response of a filter is a little complicated, but the short answer is that it does change. This brief article describes the effects of repeated poles as well as providing proofs:

https://www.dsprelated.com/freebooks/filters/Repeated_Poles.html

Hope that helped.