If adding a new [vernacular] name, then the only “requirement” I think applicable is to have a reasonable understanding of the taxon enough to recognise whether a vernacular is “in-use” widely enough to be considered to be the most used one.
Outside of that, and especially for when changing an existing vernacular in the system, I think you have to have a good handle on how other people might be using it. If someone is getting upset that you changed it, or it’s creating “name wars”, then you have quite clearly come up short in that regard, and if it were me in that situation I would immediately pull back from the situation and “do the research” to ascertain a clearer picture of what should be applied, complete with links to sources (primarily to make it easy for others to review the same material, but also to support my position). And even then, preferably via discussion in a flag rather than tug-of-war in the applied name.
Here’s another one that just showed up in my feed, and I thought “what the heck is that”. Now I certainly know this tree and they’re everywhere here, but I don’t think anyone in this area would know a “pink poui”, don’t even know how to pronounce it. Just another example common names many times are local to regions. https://www.inaturalist.org/taxa/209270-Tabebuia-rosea
The vernacular name was added in 2013, so it is not a new name for the taxa! It it is known by a different name where you live, then you can add a common name (but don’t make it the default for the taxa), and set it as default for your place. Of course, if you travel a lot then setting a place in your iNat settings is not ideal. Generally though it is not a good idea to rely on vernaculars to any degree, as there is little regulation around them, and where any certainty is required you should refer to and use binomial names as much as you can.
Not trying to discourage you but M. fusca and the changes made to the taxonomy have been an issue for about 14 months now. Only 2 people on the site can change it, probably a dozen or more requests to implement the change have not been addressed.
We need more curators interested in bird taxonomy to be Taxon Curators, I think. I think an ideal system has at least five people dedicated to a frameworked taxonomic branch (and that’s not including @loarie). Mammals are very close to reaching that minimum and I think it is one of the better curated corners of the site as a consequence. But in order to reach that for other clades, I think we need to explain certain tools better, such as Frameworks and QGIS.
The big challenge with birds is the source reference used by the site is updated once a year, so there is one period of significant activity, then basically silence for 11 months.