Thank you for sharing the link. Here’s the relevant bit from the article:

Most gas stations don’t want to install new tanks just for E15. Instead, they’re installing blender pumps, which mix the ethanol and gasoline together in the right proportion depending on which one you want. But there’s a problem: if you pump E15 into your car, about a third of a gallon remains in the fueling hose when you’re done. If someone comes along, switches to E10, and buys a single gallon for their lawnmower, they’ll get a third of a gallon of E15 and two-thirds of a gallon of E10. That comes to about 11.7% ethanol, and that might be enough to set your lawnmower on fire.

So the EPA produced a new rule: if you sell E15, you have to require your customers to buy at least four gallons of gas regardless of what blend they’re buying. That’s a big enough purchase that the residual fuel in the hose is too small to matter

Really exciting development for the climate change mitigation toolkit. Let’s hope it’s not too challenging or costly to scale up and deploy.

The recovery time, aka first hour rating, should be in the specs for the models to find one that suits your needs. There’s more detailed research on them available as well if you’re so inclined.

You can, but not as a heat pump so you wouldn’t get all the efficiency gains and it will very often end up being more expensive to run than gas tankless in the near term.