Start asking them to deliver on their own project. Just because they aren't technical doesn't mean they can't provide you with evidence of their input. Ask for

Start asking them to deliver on their own project. Just because they aren't technical doesn't mean they can't provide you with evidence of their input. Ask for more detailed specs, Spellchecked and proof read copy, mockups, copyright free images to use. Anything that will that will speed up the process for you and prove their commitment. Ask to see evidence of their attempt at marketing, surveys with potential users giving feedback on proposed features, active twitter accounts networking, competitor analysis. You need to get them to prove they're not useless. That they can contribute even outside of development. If it turns out they ARE useless...you know what to do.