I'd recommend sticking to a rack unit for FX if you have a rack preamp and power amp. It makes everything that much more convenient to carry, setup, and use.
Also worth noting that most rack FX units have multiple FX that you could run both before and after the preamp section. You do that, it's a hell of a lot of cables to accommodate.
Don't forget, in case of a system failure, it is much easier to diagnose if it's just a single rack unit malfunctioning rather than one amongst a dozen pedals.
If you go Axe FX, it will pretty much have everything you need. The FX quality is also top notch. Plenty of inputs and outputs to send stuff to FOH, monitors around the stage, your own personal monitors, etc.