Yes you can switch patches with Program Change messages. The OWL Pedal and Modular have 40 patches:
The Alchemist and Wizard come with four patches pre-loaded and you can store lots more.
You can also control patch parameters by MIDI, see this table for mapping MIDI to parameters:
Time to change patch: it's fast. I'd be surprised if any patch takes more than 1/10th of a second to start. It's really instant.