The frogs won't care if you remove them. But, if you leave them you get to watch the parents egg feed. Super cool. Also watching the little froglets emerge from the bromeliad is awesome.

 

'Mourning' is a complex mental and physical state that involves a complex conception of the past, probably an ability to imagine the future, and a well-rounded self awareness of oneself and one's place in a social reality, and possibly a learned notion of grief. It isn't likely, in my relatively untutored opinion, that any amphibian has these capacities.

Froglets of egg feeders are said to morph out larger when parent-fed, and this likely impacts their overall health as an extended early period on springtails is thought to be a tough time.

Removing eggs/tads will encourage more egg-laying, yes.

 

Froglets of egg feeders are said to morph out larger when parent-fed

I've had the opposite experience with my Ranitomeya sirensis. The ones I pulled and raised myself came out of the water significantly larger than the ones I've left with the parents to raise. The sample size is quite small (4-6 that I raised and 2 that the parents raised), so it might just be an anomaly.

 

I like to leave mine in and they do just fine and it's more fun to watch the parents take care of them and to see them emerge from the bromeliads and grow. It's always way easier. I do think you get fewer that way, which is fine with me. I would caution against seeing dart frog breeding as a money-making operation. The amount of work it takes versus the amount of money you bring in is not a great financial trade-off. If you enjoy doing it anyway, it can be a nice way to help pay for your hobby. But I find it's really difficult to actually turn a profit on it, at least on a small scale.

 

I’d really like the parents to lay more eggs, 1. Because their breeding behavior is really cool & exciting, & 2. Because I’d like to sell for profit.

There's a discussion on breeding for profit right now over here:

Breeding Dart Frogs

... it's generally a losing proposition for a whole slew of reasons. Hobby breeding will usually bring in some extra money to pay for supplements, fly media, plants or whatever but it's not likely to be a 'supplemental income' in the sense you may be hoping for.

Regarding the projection of complex emotions on to amphibians ... it's likely to be just that. I'll be the first to tell you frogs are charming, often cute and sometimes hilarious to us humans, but they don't possess the neural architecture for complex emotions and don't display them either.

Of course this doesn't mean they can be abused or kept poorly -- they're living organisms with a specific suite of instincts it's our responsibility to cater to and can certainly feel discomfort, but I don't think they 'love' or 'mourn' because they simply don't have the capacity for it.

The group tolerant frog species appear to be 'social' and insofar as they have a suite of instincts to respond to and deal with conspecifics this is true, but they're not 'buddies' and would out-compete a weaker animal to death simply as a matter of course and step over its body.

I think we can enjoy the things we find charming and funny about frogs, without anthropomorphizing them and putting funny hats on them for Instagram. 😉

I'm a big proponent of remembering and respecting what reptiles and amphibians are, and saving the snuggling for kittens and puppies.

Just a sidebar to this discussion -- I don't think you're trying to snuggle your dart frogs.