They texted me, asking for a decision. I texted back, letting them know that I'll pass but that I'll meet with them once a week for a little while to help them refine their MVP so they can communicate it to a developer. I figured it was a friendly offering of my expertise. I told them to feel free to utilize me in that regard if they'd like.
Instead of identifying the friendliness, one replied telling me that I'm either fully in or I'm out, implying that my offer was too half-assed for them. I was clear in saying that I passed on their offer to be one of their founders, so I didn't really understand what he wasn't clear on -- I plainly offered to help them refine their MVP strictly so they can execute as seamlessly as they could once in contact with another developer. I told them that when I received his response.
The other still hasn't said anything. And the one who initially responded hasn't replied to my last message. I'm assuming they're mad, although, that's not a very friendly way to reply, even after being rejected.
Now, I'm really glad I decided not to take on the role.