I found a simple workaround (or maybe this is the correct solution and not a workaround) - but I can just reverse the order of my files in a windows folder before importing to After Effects.
Would still like to know if there's a way to do thise inside of AE (other than hand sorting a thouasand images or applying an effect to reverse time sequence).
Name the files correctly when rendering. Use number padding, i.e. "myfile001" instead of just "myfile1". Furthermore, when importing properly named files, there is no need to use the Force Alphabetical Order option, as you seem to have done. Aside from al lthis, you can easiuly reverse a layer by just uing Layer --> Time --> Reverse Layer.
I actually did have the files named as you sugested (with 001, 002, 003 as opposed to 1,2,3 which I originally posted for simplicity), and I did NOT force alphabetical order. I just assumed that since AFX knows files are sequenced in upward chronological fashion, it wouldn't matter the sort order in my windows file (but that doesn't seem to be the case).
I'll try the Layer>Time>Reverse layer.
Thanks again for the help.
Reversing the pane order on the computer worked. Naming change did not. Need a better solution.