The CA18, as per usual is gettng a bit of a bad wrap here.
as an example, I was running an unopened factory CA18det with GT2871R turbo and supporting mods at 20psi (0ver 200rwkw) for over a year before it wore out. Bare in mind, if this car was started, it was drifted. So it didn't have the easiest life. given that the engine was over 15 years old when i got it, i think that is a pretty fair life span.
My strongest suggestion is to fit a quality oil cooler. This offsets the oil return issues by increasing the capacity.
Basically.........if it were me, i would be fitting a CA into the rolla.
In fact i would do it to mine if i could convince myself to spend any substantial cash on a rolla. I can't even bare to part with the cash to fit a stock 4age.