IMHO etiquette might be the biggest problem in this whole thread, not to get on anyone but it feels like the thing that most got to
@Mbernal was not what anyone's advice was but the way he was being talked to, which is likely made worse by how text makes everything feel more blunt if the writer doesn't have a flare for prose.
I think telling someone they're being cruel to their animals when they're obviously pretty broken up and that all the things that worked for them before are stupid is likely the worst way you could possibly try to get them to listen to your advice.
As to cycling with fish in, if you dose high with things like turbo start it shouldn't hurt them, though you want to watch the levels and do big water changes to keep levels down. IMO fish-less with ammonium chloride and cultures is just the easiest way to do it without any hassle.