I pushed an Invoice to QB and then later made changes to that Order: are those changes reflected back in QB?

No. You will need to edit the Invoice in QB and make the same changes manually.

Once Vinosmith has pushed an Invoice to QB the relationship of Vinosmith + QB regarding that Invoice is essentially complete and there is no further communication between the two systems as far as that Invoice is concerned.

The same is true vice-versa. If you made changes to that Invoice in QB then those updates are not reflected back in Vinosmith.

If You Need To Push An Invoice to Quickbooks Again

Once Vinosmith pushes an invoice to QB it records that transaction and will not allow you to push it again.

If you need to make changes to the Invoice and push it again you will need to remove Vinosmith's knowledge of that action. You can do this by pulling up the Order and at the top of line item list it will say

Quickbooks Invoice Created on ... with a link for Delete - click that Delete link.

You can now push the Invoice to QB again.