That looks like a good as any glass bowl, should work like a charm.

About telling them apart from their feet, I'm guessing you're talking about the nupital pads. These are like a dark brown thumb on their front feet which they use in amplexus. Some frogs have these constantly, but red eyes develope them during breeding time, and they then disapear again. So you can't use that right now. Just give it some time and wait for it to call Or get some nice picture in a month or so, when regularly fed, to see if it's quite plumb or not.