So I *think* i understand what you want to do.
you want the local share to work as normal and only be useable withing your own network
you want the http share to be open to everyone and their dog and be visible on the entire internet
you want the ftp share to be identical to http except that only you can use it.
the http share does not work like a normal http server (apache) does. the NAS simply shows what is in the share via the browser, so you couldn't throw a random html file in there and expect it to work like it was on a real web server. for this reason you HAVE to go through the main load menu of hte NAS (where it shows the shares) and click http. I'm not 100% sure about this, but guest account doesnt mean it lets anyone in. what it means is that you type 'guest' as the user and 'guest' as the password (at least i would think so, it might be 'anonymous' and no pass)
so when you say you want to go to http://
<sever-addy>/http/index.htm you are trying to *serve* a webpage
(also i dont know about the new ED mini's, but mine dont even do a real html file ever, it just builds the page from bash code...somehow)
as for you ftp... you need to look up how you do ftp in a browser. you type it in like so "ftp://<username>@<server-addy>" this SHOULD bring up a prompt for your password. Usually FTP servers, if they dont have guest ('anonymous' user and blank pass) accounts, ask you for a user and pass, but the ED Mini might not be that smart. (i know my super old version of it acts like this but i thought they would fix it)
i hope i answered everything / understood what you wanted.
also as a side note you are in the wrong forum really. you should be in the v2 forum. this forum is for the old ED Mini's which had only 500GB max in them.