Happy to hear that your commerce account was finally approved.
Maybe it is just a matter of time... well 3 months at least it seems.
Anyway in the meantime I have posted negative feedback to Shopify in their questionnaire which is in the Facebook app section of the dashboard. Maybe if everyone does the same Shopify will put some pressure on Facebook to look into this.
If all your products are approved, then you should be able to post pictures on FB and then manually tag those pictures with the link to the items in your shop. This will link to your shop even though the shop is not published. You can still run ads and tag products in FB and all the stats and analytics should work normally. (assuming you have a similar set of circumstances)
I have the following hilarious set of circumstances:
1) Shopify pixel is running on FB without errors - updates to items in my Shopify portal will automatically update in FB shop.
2) On one occasion I published an item that was against FB policies (after my shop was rejected). I amended the pictures to be in line with the policies (deleted the alcohol related picture). I submitted for a review on this one specific item and within hours the item was approved.
3) I can edit all the items in my shop manager on the FB side and see all the attributes port over from the Shopify pixel.
4) I can tag items in pictures on my news feed and this will link to my FB shop and I can further click through to both that individual item (link to purchase through my website) and I can also click through from that page and see my FB shop and all other listed items and link to purchase all items on my website.
5) The only thing not working is simply the "publish FB shop". This in turn doesn't allow me to setup instagram tagging or instagram shopping on my linked IG profile.
It's obvious from the item tagging that the shop is up and running and that there are in fact no issues with my commerce eligibility or any of the items in my shop. It's simply some kind of programming error on FB side.
At this point I'm resigned to this functionality being good enough and I'll hope that someday it's fixed. Sadly, FB support is not worth working with as they will not do anything to fix or escalate the issue.