After watching them more:

I think they'll get on okay with ghost shrimp, and in the event that one gets eaten on occasion, at least they're eating well and they are often sold as feeders after all.

My frogs seem really healthy. I haven't seem them at the top much, and I think they're definitely fine/I was being a worry wart. They seemed to have learned where the food bowl is now and when I'm feeding them/get their faster, too. Which is a definite win so their food isn't in there long.

I tested the parameters again tonight during a water change, and they were at 0 ammonia/nitrite and 5 nitrate (before the change). So the nitrate is at about 5 or less now after the water change. I may test for hard metals at the pet store next time I go, but I think things are going well for the frogs and I should be good! :D (horray!)

I've been keeping an eye out for any abnormal sheddings, too, and they've been really smooth/quick/not stringy or anything so I think that's also a good sign. :3