Custom Edit Record URL for EOTI

Hello All - Here's my situation:  I have a community app that captures Parents in the Parents Table (name, email, cell).  I then have a Parent/Child relationship (no pun intended) to the Child table [Child 1 (name, age, dob), Child 2 (name, age, dob), Child 3 (name,age dob)].  I would like my workflow to look like this:

1. EOTI audience visits my registration link
2. Parent registers by entering their initial information (regular html form to parent table)
3. Parent receives email confirmation of registration (pipeline to mail chimp)
4. In the body of the email, there's a series of welcome text and other information.  At the bottom, there will be a link that says "Click here to complete registration and add children."  The link will allow them to add 1 or many records to the Child table.

The only way I can think of to achieve this is to create a Pipeline:

1. Trigger - QB Record Created
2. Action - Outlook Email - where the body of the email contains the Add Record API URL linked to the parent record. 
   
   Right now, I have constructed the URL by entering the following text in the body:  
   
   https://andtechllc.quickbase.com/db/bt2mpv3zh/form?a=er&rid=Record CreatedRecord ID&rl=ct&page=1

Is this the right way to do this?  If it works, I can see it working for the first child, but how do I ask them if they want to add another child?

I hope this makes sense.  What other information do you for me to help you help me???