Variation Wizard Feed File Problem

I searched and searched and found people with similar issues, but none seem to fix my problem.

I’m trying to add a variation to an existing family. I can’t add the Parent ASIN using Add a Product because it doesn’t give the option to click Sell Now, as it’s a placeholder and not actually for sale. When I go to Variation Wizard, I see all of the current variations listed. I’m able to click Sell Yours on them, etc. and add them using the template generated. On the top of the list is the Parent ASIN, but there is no Sell Yours option, and no seller SKU available since it’s not yet in my inventory. When I generate the template, the parent ASIN is at the top of the list, with a generated Seller SKU. If I have a variation in my inventory, that shows up beneath the Parent ASIN.
I have the Parentage cell of the Parent marked as parent, and child marked under the child ASINs. Variation cell is Flavor-Size for all of then, as it was autogenerated by the Variation Wizard, and is correct.

The Problem:

I generate the template, but there is no UPC/EAN/GTC/ASIN autogenerated, presumably because there is not one listed under the Parent item in Variation Wizard. I do not know the UPC of the parent item, since it is not viewable on Amazon to my knowledge. So I write in the ASIN identifier and select ASIN from the Product ID Type cell. When I upload the feed file, it does not add the correct Parent ASIN to my inventory. It creates a whole new amazon listing with a new ASIN, and uses the seller SKU that was attached to the correct Parent ASIN from the feed file. The new ASIN created seems to have no connection whatsoever with the family/variations of the Parent ASIN.

Seller Central Support is nearly 100% unhelpful, just providing canned talking points I’ve found on their website already.

Any assistance would be very helpful.