Energy stations (gas) pay pretty well. Right now Tesla owns most of the electric world and even if their cars fail could become a dominant energy provider.
Do they? I don't know what the situation is in North America, but here the business model of fuel stations is to sell fuel at near-zero margin and make the profit from impromptu sales to fuel customers in the attached convenience store.
Margins are tight in the US, a typical gas station has margins comparable to a grocery store. Something in the neighborhood of 2% IIRC. Adding a convenience store definitely helps increase that.
Generally you aim for 1/3 gas, 1/3 tobacco, 1/3 snacks. While gas is by far the lowest margin, it is very high volume, with many people not buying anything else.
Probably, but since most charging will be at home, there will be a lot less total $ in play. Great gig if you can be on a route people travel long distances, but otherwise not much profit.