Are component/separates any better than fullrange or coaxials?
Usually, yes. Using separates allows you to position the drivers independently and more carefully, which will give you greater control over your imaging. For best results, try to keep the mid and tweeter as close together as possible — this will make the two drivers act more like a single point source (which is ideal). For rear fill applications, however, coaxial speakers will perform fine, as imaging is not a primary concern. However, it is very common to use a low pass crossover with the rear speakers (at 2500 Hz) since rear-fill is intended to produce “ambiance,” and high frequencies (> 2500 Hz) can confuse the soundstage, making it appear that music is originating behind you.