ModelBuilder tools not recognizing output of Iterate Feature Classes

[Beck_B]

I have a model to 1) select parks within an administrative boundary 2) iteratively select each park separately 3) select all observations of animals within each given park 4) group those observations by taxa (the field name is Class) in their own feature classes. My desired output is a series of feature classes showing where different taxa are in each park (e.g. River_Park_Fish, River_Park_Mammals, Forest_Park_Mammals). I'm using ArcGIS Pro 3.5.

Everything in this model runs until it gets to the final Export Features, at which point it gives "ERROR 000732: Input Features: Dataset I_RIVER_PARK_Class does not exist or is not supported. Failed to execute (Export Features (2))." I know this means something is going wrong with the output of the submodel Iterate By Taxa, since this is the part that should be producing that output. I'm not sure if it has anything to do with the fact that the submodel Iterate By Taxa is functionally empty (see below submodel) when I drag it in, since I need the input features and the fields it's grouped by to be produced by the larger model.

My big question, then, is how do I make the output of Iterate By Taxa submodel (animal observations grouped by CLass, the type of animal) into a format that Export Features can actually process?

Here is my model and an in-depth description of what each step is supposed to do.

1. Select parks within an administrative zone (e.g. southern region)

2. Iterate feature selection, grouped by park name, to get all the parks (e.g. River Park, Forest Park, Rock Park)

3. Do Calculate Field as a precondition to replace any spaces in the park name with underscores so other processes can actually read it (e.g. River_Park, Forest_Park)

4. Use Select Layer By Location to select all observations of animals (PTSOBS, polygon feature class) that intersect with the given park (e.g. all of the animals within River Park)

5. Export Features so the selections in the layers are now all their own layer (e.g. a layer of all the animals within River Park, named just River_Park)

6. Feed that given layer of all the animals in one park into an iterator that groups by the type of animal/taxa (e.g. fish, mammals)

7. Calculate value to remove spaces (e.g. birds of prey to birds_of_prey)

8. Export or select the iterated features to their own individual layers (e.g. River_Park_fish)