What are the advantages and disadvantages of different pedal formats for a recumbent? We're reasonably familiar with pedals on conventional bikes.


Flats are convenient for normal shoes
Clips and Clipless provide foot retention and option of pulling up


A recumbent has additional considerations


No way to "rest" the foot on a pedal because your foot pushes from behind nor down from on-top.
Heel strike - just the same as toe overlap for smaller DF bikes, heel strike is where your front wheel/s touch your foot while turning.
Getting started from stopped - pedals are a lot further from the ground so raising your foot in time for the second push stroke while maintaining low speed balance.
Danger of "leg suck" should your foot fall off the pedal and hit the road while rolling.


What other considerations are there for choosing a pedal for a recumbent bike or trike?
You can add "heel slings" as a choice too.  They hold under your foot's heel.

They fit flat pedals and do not provide any cliplike retention.  Instead they are a hammoch for the back of your foot (heel) to rest in.

http://www.bentrideronline.com/?p=5131

These wire ones look uncomfortable, but shoe choice comes into it.  Prolly not good for flipflops or sandales!



http://www.jsrldesignllc.com/  and    https://tadpolerider2.wordpress.com/2017/09/15/jsrl-design-vs-terratrikes-new-heel-slings/

Terratrike sell some that are more strap and less like a garrotte-wire.