How to Plumb Sink to Drain
1) You do not need to add a cleanout if you put a 45 elbow on your rough in. You probably want that 45 plus a short straight piece of ABS DWV to make it easy to adjust your P-trap.

2) Go with the PVC P-trap so you can easily adjust the location of your joints. You don't want to glue up the ABS and have to shift your tailpiece a fraction of an inch, or start at the tailpiece and have your trap glued to your drain pipe with just a tiny bit of engagement because your stub is a fraction of an inch too short.