Given that any module or changes that allow text commentary on taxon pages is some time in the future, there are at least 3 things all users can do right now that can help with your points.
- the about tab on the taxon page sources from the Wikipedia article, assuming one exists for the species. Anyone can of course edit a Wikipedia article, or even create one which should then get automatically picked up on the taxon page
- on the About tab of the taxon page is a More Info sidebar. All users can contribute to this, if you know a good external reference page for the taxa, with id tips or whatever, you can add it.
- all users can update place checklists which then feed the map on the Taxa page. Just go to the relevant place, click the checklist page link towards the lower left and add away (including establishment means). If you have access to a list of species known to be in a location, there is a tool to bulk add multiple species to a checklist (which is also a good way to find missing species, as when you try to add it, you will get an indication). Unfortunately, there is no reverse functionality to bulk add a single species to multiple checklists.