Looking for advice - cracked rear hub along bearing races - How to buy a new rear wheel?
The bearing cup is toast from being ridden with a bent axle. The hub shell does not appear to have structural cracks. 

With a new axle you could potentially get some life out of it, but you're probably on the right track with replacement, especially if this is a bike you're riding indefinitely.

With either the freewheel or cassette route, the sort of wheel you'd need are very common repair items that are easy to get from a shop or internet retailer. You need any rim brake 135mm 700c hybrid freewheel rear wheel, or any rim brake 135mm 700c hybrid cassette rear wheel plus a new 7 speed cassette and a 4.5mm cassette spacer. 

Replacement hybrid wheels with 7-speed freehubs used to be commonplace and are a little technically superior when applicable due to their wider flange spacing, but aren't made by any large wheel producers I've seen in recent years, in part because those bikes are aging and in part because of the explosion in repair wheel compatibility permutations shops and wheel producers have had to deal with in the last decade. Hence running an 8/9/10 with a spacer has become the norm for replacements.

Given it's bent axle problems that got you here, there's a case to be made for switching to cassette. In almost all cases it makes sense to start out a new chain at the same time, and the potential gotcha then becomes the wear state of your chainrings.