Hi,
1. There is no option to remove the name field from Joomla. It's a field required by Joomla for the creation of a user account.
You can potentially modify the code to remove it and use the custom fields value instead but you'll have to modify the code for that.
Again, moving some of the custom fields instead of the name field won't be easy as the custom fields are displayed in one view all together. It's not impossible to do, but will require some custom development.
If these are things you really need to do, you can contact our partners for a quote:
www.hikashop.com/home/our-partners.html
or use our commercial jobs forum to try to find someone.
2. That can be changed with translation overrides:
hikashop.com/download/languages.html#modify
3. You can edit the files of the view "checkout" via the menu Display>Views of HikaShop and add your text where you want it.