Using OneSpan email invitations in addition to session token URLs - will this work?

Hello,

In this question I am not looking for any technical details or answers to how to integrate as I am fairly comfortable with our ability to do what is needed.  Instead, I am just looking for someone who might have done this before or someone from OneSpan to look over what we want to do and tell me if the OneSpan Sign SaaS solution will allow this or not and tell us if there will be unforeseen constraints going about it this way.

Background

We have an internal business client who is building a "document exchange" type website.  This site will allow a customer to see at a glance all pending esign processes they need to complete.  The customer will be able to click into any one of them, at which point the website will redirect them into the OneSpan signing experience.  Ideally, we would also have the systems in place to handle customer communications, however at this point in time this business system is not able to handle the customer communications.  To this end, we want to continue utilizing OneSpan Sign for its email invitation capabilities, which come with the added benefit of enforcing signer order workflows.

The Flow

At a high level, the flow would be something like this:

1. During account configuration, we would customize the email templates in the OneSpan account to remove the signing url that comes as default and replacing it with a static link into our own 'document exchange' website.
2. When a business system creates a new OneSpan transaction in this account, OneSpan will send out emails to the signers containing our link instead of the signing URL.
3. Behind the scenes, our systems will communicate that a transaction was created and sent to the signers.  This will be used later by the document exchange when the customer logs in
4. The signer will open the email they got from OneSpan and click the link, which will route them to the document exchange website.  There they will be required to authenticate
5. Once logged in, the signer will see an entry for each of their pending signing transactions - from step 2 above
6. When the signer clicks into a transaction, the document exchange will request a single use session token from OneSpan, construct the signing URL with it, and redirecting the signer where they can complete their signing

Thank you!