Observations record individuals, and thus annotations describe the individual being recorded. So for dioecious plants, annotating an individual plant as male or female adds value. Monoecious and dioecious describe a taxon. Annotating an individual plant as monoecious or dioecious is redundant.
Again, iNat observations record individual organisms. Just add the Copulating Observation Field or a similar one to an observation showing a mating pair.
Do you have examples of this still appearing as an option for viruses and bacteria?
Those are so rare that I think you can easily address them with Observation Fields (eg https://www.inaturalist.org/observation_fields/14486) or add them to projects like Amazing Aberrants.