Yeah, always change the oil and antifreeze when doing the LIM/UIM job, regardless if they mix or not, I'd not even drive the car again until this is done, better safe than sorry, especially since changing the oil/oil filter, and antifreeze is not that costly.
As for rotors, I always tend to go AC Delco, but if the car is just a daily driver, then you could get RAYBESTOS 56325R, they are like 24.00 from Rock Auto.
The ones I prefer are almost double the price, but if they are affordable they are what I'd go with.
2006 Pontiac Grand Prix GT with SC
1996 Buick Park Ave NA