Pre-order With Buy All?

For my next "will this work" question...

I need to set up some school galleries with a pre-order component. I want the parents to pre-pay for either a single pose or multi-pose option, both including the digital downloads. Then when they come back later to get their downloads, they can purchase additional prints if they like.

The single image seems simple enough, but what is the best way to do a multi-pose package if I don't know how many poses it will be and don't want to limit it? Some kids are dynamic and we will shoot 5 or 6 poses, and others are happy with 2 or 3.

Does the Buy All digital option play nicely with the pre-order function?

I was contemplating just uploading the pre-purchased digital images as free downloads but I would really like to have them attached to an order so it's easy to track the downloads and order completion.

A buy all with pre-orders won't work because there are no photos yet. 

You could create a collection that includes 5 products and just say it includes up to 5 images.  

Or if they are just paying one price for 1-5 images, just add free downloads to the gallery.

"You could create a collection that includes 5 products and just say it includes up to 5 images.  "

Is it possible for them to check out without filling the collection if they have less than 5 images available?

Yes, as long as " Require all products to have photo selected." is not checked for the collection. 

You can also check the " Do not show what products are included in the collection." option for the collection so it doesn't show them it includes 5 images. You can add to the description that it includes up to 5 images. 

That should work perfectly!

If I set up a pre-order price list that has the digital options, can I set the gallery to switch to a different price list without those digital options when the images are populated?
The purchaser will already have the digital item purchased and needing to add images to it, but if the gallery no longer offers digitals will this still work?
(I'm worried that people will get confused and try to re-purchase the digitals when the images are available.)

You should be able to change the price list without an issue.