Well, the loading thing is easy right as rg’s have a while loading property. So do what you want there.
For “no more results” it might be far easier NOT to use the same element.
Not in front of a machine and I’m not SURE how ext scrolling lists report their cell index values. (Test it, experiment, right? I think they are like full lists rather than fixed varieties, but FYI.)
Anyway if they are like full lists:
Put a text element in your cell that is only visible when “this cell’s index is…” the RG’s source list’s :count.
That will indicate list end, right? (Say source list is 124 things. Cell index 124 contains the last item in the list and there are no more items to display.)
It should be obvious why we put the text element in the cell. (If not, it’s because “this cell” only exists inside of the context of the RG itself.) In effect, what is happening is each cell is asking itself, “Do I hold the last available item?”