Can people see a group's name when opening my shared link, and not my real name?

Thanks for your post, Dweb. 

When signing up for a Dropbox account, you’ll be asked to create a username indeed. 

Once the users you shared your folder with open the link you’ve created, they’ll inevitably see your username, apart from the name of the folder. Also, keep in mind that your email address will only be seen in case you add it to the name of the folder you’re sharing (otherwise, it won't be visible anywhere in the shared link). 

So, if you don’t want your real name to appear when opening the link, but a different one, or even the name of your group, you’ll need to make that your username (you can set whatever username you like, as this doesn’t affect your Dropbox payments/plan - this is something that's totally up to you).

Now, regarding changing your billing cycle from monthly to yearly, you can do this anytime you want during the month (the changes you’ve made will take effect upon the expiration of your monthly subscription/at the end of your billing cycle and you'll be billed for a yearly plan after that). 

Let me know, if you have more questions though.