Mixed opinions on the water features...
I know a few people with large pond type features, some deep pools etc who have had no issues.
However there have been plenty of people who have apparently had deaths due to water features (mainly drowning) with what seems mostly tincs, I dunno why that seems to be the unfortunate subset, but it is.
There was also the issue of the water itself causing issues, apparently if you have water and it's just 'standing' or even moving but is not 'filtered' it can cause bacterial/fungal infection for the frogs sitting in it, as some like to do. The easy way around this seems to be having water good enough for fish to live in, aka filtered via a fish filter or equivalent, which is very easy as all you need is the water flowing over/through something with enough surface area for bacteria to colonize, a simple sponge filter good enough for the volume of water, and use primed water (Prime de-chlorinater etc) or even better just let the water stand for several days before adding it.
People seem to have success with arboreal frogs like pumillio, rants, and with epipedobates . Either way I think if you do it there will always be at least a degree of risk, you can make it as safe as possible with multiple easy to climb exits and branches.
They can turn out to be some very striking vivs when set up right, a bit of extra work and the associated risk, but gorgeous!