2 crop overlays at once?

Sounds like you are describing the need to crop multiple product photos or similar with the product centered within a specific aspect ratio crop?

So, one of these 2 options may help you:

1)

Apply an aspect ratio crop with padlock locked (use the dropdown beside the padlock icon in crop panel to select AR)

Adjust as needed with the cropping tool with "center" overlay

When you switch to your next photo press Shift-A

(this applies the same locked aspect ratio as the previous photo)

Repeat with other photos using Shift-A as you get to the next one instead of R to open crop panel.

 2)

Leave cropping as the last step to your workflow (this will prevent changes from happening if you use previous button or sync with cropping checked)

Open photo #1 and apply a specific crop aspect ratio with the padlock locked

There is a dropdown list of aspect ratios to the left of the padlock icon.

Do not adjust the position or size just yet, we are just applying a locked aspect ratio. (Call this the pre-crop)

Then sync the crop only to other photos that will need this aspect ratio (This locks in the aspect ratio of the crop for all selected photos)

Then start making your crop adjustments with the "center" overlay active to repostion/resize

As long as you do not change the aspect ratio it will stay locked to whatever was done in the pre-crop step negating the need to view the aspect ratio overlay, repeat for the other photos.

To answer the question: no, there's only one crop at a time. I'm not sure I understand the problem, however. If you need to change the aspect ratio of multiple images, then can't you copy/paste that? Or select them all and change the aspect ratio while 'Auto Sync' is enbabled?

You have multiple images that each need to be given both aspect ratio / crop A, and B?

Perhaps consider method 1: highlight 100 images in a folder that currently show crop aspect ratio A. Add these to a new Collection, as virtual copies. They show doubled in the folder now. Optionally, you can filter the folder to not show virtual copies. Highlight all of the virtual copies in this new collection, turn on AutoSync, impose crop aspect ratio B. Downside: these virtual copies now have independent editing from their master image, so each will not automatically reflect any new editing done to the other. 

Method 2: apply whichever aspect ratio shows more of the image - say, A. And those can be exported normally. For your exports with aspect ratio B, set up a suitable dimensions borderless page layout in the Print module, filling the page, with the appropriate resolution, with the image cell set to Zoom to FILL mode. Save this setup as a named print page template. When images that show crop A are exported to JPG from the Print module using this page template, they will on-the-fly self crop themselves down to the B aspect ratio without requiring any virtual copies as an intermediate. Downside: this crop is not visible within the image library, only in the exported copy (or as a preview of that in the Print module). Upside: either form of export will always automatically show the same latest edits, because they will both derive from the same thing.