for the cart, SKU number looks like fix that, thanks.
I also found that previous blank pages issue still happen , I don't know why? after all updates still not stable.
For the child-menu, your code not working. fyi, I've had an issue with this before and other admin in GK gave me this code:
.gkMenu > ul > li .childcontent .childcontent {overflow: visible !important;} - also not working.
i don't know if this will help you figure out, why this problem persist even after several updates.
Above, I've put all info regarding the access FTP and Joomla.
thank you
-Martin