Dear client,
I have regenerated the issue and understood what is exact requirements.
I can develop a adon plugin for woocommerce that will have both those issue fixed.
For the second issue, I am sure about how to implement it but for first one I need to do a try once. So, if you are willing to award this job to me, I can test it before I confirm.
Also, you mentioned about that you want to use this plugin on many websites. So, please let me know which are the (or which lowest) WC version you want the plugin to be compatible with?
Let's discuss and I can explain why I am pretty sure about getting this done perfectly. And ask right away any questions you have about me.
Thanks. Let me know best time for you to discuss further.
Will be waiting for your response.
P.S. Consider 5 Star Feedback with 100% Completion Rate.