Playing around with some suggestions on our test server. Here’s what a moss observation looks like after Sex has been removed from Bryophyta, and Gametophyte and Sporophyte added as Life Stage options:

To which taxa would something like this apply?
What’s the use case here? Will it aid in identification or with seasonality/phenology charts? Marking a plant of a known bisexual species as bisexual seems redundant to me, but I’m not not a botanist.
What would the Annotation (eg Life Stage) and values (eg worker, queen) bee? (pun intended)
I don’t have deep knowledge of bird life stages - is immature a generally agreed upon life stage, and one that is readily discerned from photos for many species?
Annotations have a limited list of discrete values, it’s not possible to search for an enter another taxon as an annotation. You can use Observation Fields for this at the moment.
This seems pretty niche and would be better suited as an observation field.
I think a good fit for a long-gestating photo annotation functionality. So basically being able to label each photo in on observation. But something like that will have to wait until other features are completed.