firemouths are the only one that ive had on that list that's bred for me. I never planned on breeding them so i guess that makes them relatively easy to breed lol
It is my understanding that leaf fish (SA species) are not particularly difficult to breed, but the others besides the cichlids would likely be a challenge.
Most would be a challenge just due to space issues, as well as sexing the fish, with the exception of more common fish like the firemouth. Also with eels, several species breed in freshwater but the eggs and young carry out into marine or brackish waters. Not easy to replicate that at home!
The only things "easy" on that list is the firemouth and with enough space chocolates. Ive heard of knives and other gobies breeding but it was not easy at all. Ive also heard some success stories of bichir but if you want easy breed your firemouth his current size is fine. Make sure you have male and female as they can be tricky to sex.