I thought I'd share a few hang-ups I had to work around yesterday and today on this.
1. Publishing from the Share ribbon publishes all layers in the Contents pane, while right-clicking on a layer and sharing from the context menu only publishes the selected layer. I assumed that any related tables would also get published as well when doing the latter; this was not the case. I had to use the SHIFT key to select both the feature class AND the related tables in the Contents pane to get them to publish as one hosted feature layer when right-clicking on the feature class and using the share context menu.
2. Collector does not like < or > signs in the names of layers in your web map, and probably some other special characters (though it seems fine with dashes and parentheses). The tables as I created them in the geodatabase of course do not have any special characters in their names, but while you can rename them once published and added to a map with spaces and other characters you couldn't normally use in a feature class name, certain symbols like < and > gum up the works.
3. Another hangup I had from the start with this project was that I couldn't get AGOL or Collector to behave the way I set it up in ArcGIS Pro with subtypes and domains. I have three subtypes in the layer, and a different domain list to be used for the same field for two of the three subtypes. For the third subtype, I don't want it to use any domain at all for that field. This works fine in ArcGIS Pro, but not in AGOL or Collector. What I had to do was create a third domain for the third subtype with the one value in the domain list that I would always use in that field.
Cheers,
-Neil
Neil Curri, GISP
GIS Analyst, PVE, LLC
Vassar College Academic Computing Consultant