If you need a "strong and complete e-commerce solution" you should use Magento or for lower requirements Prestashop. If you want to manage warehouse, orders, etc outside them, plug them with Odoo (or any other system you like). Odoo 9 has a new connector system to do this.
If you like Odoo there's still the option to use its e-commerce features. Even if they are pretty immature you'll have a solid base for them and, above all, you will not need to worry about setting up, maintain and keep in sync 2 different systems.
Is still not clear to me why you want to use Plone in your case. If you do not need granular permissions, per-content permission, advanced workflows, document management, etc then you don't need it. About page design: Odoo has its own page builder and i works pretty nicely.
If you don't need an e-commerce but just "sell some stuff from Plone" then go w/ one of the products that have been mentioned already, or use some fancy JS lib like https://cartjs.org/ to just add a cart and code backend stuff yourself.
As you see, there are many "if" here 
so it really depends on the balance between
- how many ecommerce features you want
- how many CMS/DMS features you want
- how much time for coding you have
my $0,02