eeev77 great questions! Let me try to add some insight. I will try to go in order to make sure I do not miss anything.
First, in terms of your example with the supplier "Megir" and copyright products you'll need to proceed with caution. If the brand is the supplier's brand then yes you can sell it! For example, if the supplier "Megir" has watches branded "M Sport" or a brand that is clearly their own then yes, you can sell it. However, if they are selling a "Rolex" branded watch then no you can not sell them!
Customized packaging is not yet a possibility. It's been in the works and a huge pain point for merchants but right now there is no way to create a custom package when selling items in single units. Of course if you have an agreement with the supplier and maybe order in bulk it may be possible to organize this. However you will need to reach out to them separately for this.
Otherwise you will need to rely on their packaging. But do not despair! All the dropshippers you see that are successful are making it work too. It's possible you just need to change your mindset about it. I too am looking forward to custom packaging in the future!
Lastly, yes, you can create a brand and dropship from it. If you create a watch brand named "simple" and then sell someone a clean, minimal watch then it would be branded by you without having your companies name on it. Hope this helps!